Ok, here we go. I can write a book on this topic really.
To fully understand why the Spanish national team is consistently inconsistent has as much to do with football as it does our culture and politics. It is well documented how regionaly disperse the country is compared to a France or England, and much more so than Italy is. The press bleeds the point dry for every major tournament at how many Catalans, Basques, Andalucians, Castilians, etc are selected for La Seleccion. This is written about incessantly, because there has to be a reason for failure and it is summed up by regionalistic autonomy and pride. The Spanish term 'morbo' sums this cultural element up perfectly. I can't even translate this into English, but it is essentially a sentiment between the regions that divides them and is influenced by language, politics, club futbol teams, and history. Really tough to articulate this phenemenon in any language other than Spanish. I mean....afterall...that one word means what I write in that sentence! I think most people know this, or can be explained this verbally any Spanish national. I will focus on the major tournies since 1986.
Let's go tournament by tournament though, much of the way you have done.
WC 86
As you mentioned el buitre joined Eusebio as the only men to score 4 goal in WC match. Also, Michel had a goal famously disallowed vs. Brasil in that match. You may remember how many times they showed that goal (seemed more than the Morientes header vs. South Korea provided by Joaquin in 02). To be honest, this was one of the better Spanish sides at a WC. The 5-1 demolition of a very good Denmark side was truly a shocking victory for the country. I fully agree that if we had just outlasted denmark, we would have given Argentina a better match then they did, but I doubt we would have won that semifinal match in that hemisphere. The missed penalty was by Eloy (Naturally the press claimed he missed because he was from Asturias) Of note here....I didn't realize it at this time, but this would become a common theme for Spain at many of then next major International tournies. That being...losing a match in the latter stages, where advancement would have set up a tremendously interesting matchup between world powers. More on this as we go on.
Euro 88
On a personal note, this tourney belonged to Milan players. Baresi established himself as the best defender in the world that summer in Germany, and the Milan Dutch trio were simply brilliant. As for Spain, it was always not favorable to play the Germans in major tournaments during this era. It is that much more difficult to play them on their soil, in Munich. The 2-0 scoreline was expected. As for that match with Italy, Baresi, Maldini, and Bergomi set up an Italian wall in Germany and won a classic tempo Italian match. They solidified, played the counter, and Vialli scored the winner 20 or so minutes from time. It was well documented that the Italians just have something extra when they represent their country in major tournaments, and this match was no exception.
WC 90
Correct, Michel hit a hat trick vs. Korea, and he hit a penalty in the 2-1 win vs. Belgium. To be fair, this Spanish side wasn't too fancied as many fo the players were now older and close to international retirement. Going up against a unified Yugoslavia that was just entering their golden age was always going to be daunting. That side featured Pancev, Boksic, Suker, Stojkovic, Jozic, Prosinecki, Savicevic and plenty more I am sure. They easily would have won Euro 92 in my humble opinion. It was an exciting game as all three goals came in the last 10 minutes, but we only scored one of them. If we win....we play Argentina in the QF on european soil.
Euro 92
Luis Suarez was replaced by Vicente Meira as coach of the team for the qualifiers. Needless to say he was axed. This is important, because Javier Clemente became coach. For the record....Clemente is a Basque.
WC 94
Not much to say here except about the match with Italy. Very similar to the 88 match, except this was a QF and it ended 2-1 not 1-0. Baggio's legend certainly mentions his late winner vs. us in this match. If we win...we beat Bulgaria, and we lose to Brasil in the final.
Euro 96
The only thing that needs to be said here is that Kiko scored a legitamate goal vs. the hosts that was disallowed. This one still bothers me. Game ends in a draw. We lose during the penalty shootout.
WC 98
Who to blame? JAVIER CLEMENTE. This man decided that Zubizarreta was first choice over Canizares. His reasoning? Because Zubizarreta was a Basque. Marca (which is a Madrid based publication and ardently advocates Real Madrid and that region) blasted this man endlessly for 8 years, which started because he was the tactician to drop Butragueno from La Furia Rojo. This latest comment was simply unbearable. Everyone saw a 37 year old Zubizarreta lose the Nigeria match. A drab draw with Cesare Maldini's Paraguay did follow the 6-1 thrashing of Bulgaria, but Paraguay beat Nigeria by 2 or 3 goals to advance.
Euro 00
After losing to Norway 1-0, my expectations were gone. (Depor keeper was Jose Molina, and yes he was responsible) However....that match with Yugoslavia was an absolute classic. Back and forth. We went down 1-0. Leveled it. Went down 2-1. Leveled it. Went down 3-2. Won a 90th minute penalty, converted and then found the winner in stoppages for a 4-3 scoreline. What we saw here was something that no could deny we were capable of, but we never enjoy luck like that in tournaments like this one. Like you said, we played France tough. That first half was exciting and ended with Raul missing that penalty.
WC 02
The only thing I want to mention here is that if Italy didn't get robbed vs. Korea in the second round, the QF would have been Spain vs. Italy. Oddly enough, Spain were cheated even more than the Italians in that QF, which would have setup Germany-Spain in the semi.
Euro 04
I take pride in that we did not lose to Greece. However, it is a shame that we lost to Portugal, which is a country we have dominated in International football forever.
Everyone can remember WC 06. Spain was fancied against the French, and that was the match that ignited the French to the final of that tourney. I do honestly believe Spain would have beaten Brasil in the QF on European soil though.
So that is the recap. I really wouldn't mind starting a post to further clarify the whole cultural aspects of the country and how they play a part with our national team, but it is almost better to have your own interpretation of it. Spain's culture and history have created this conundrum known as La Furia Rojo. Our talent and individual players should see us as one fo the best, but instead we are perennially labeled dark horses that never finish. I always look to the European Championships with great optimism. We have won it before, and we are capable of doing it again with some luck. I just want to see a Spanish capitan (regardless of what region he is from) lift the Henri Delaunay trophy.....and maybe even a Jules Rimet variety.