I think Milan is a far cry away from being as "doomed" as a lot of the fans think. Some people legit think Milan is close to hitting Ajax level of obscurity.
To me, Milan will survive off its brand for a long time. While it's true that our declining finances are worrying and will probably keep us back several years from the peak we once hit, it's not so bad that we can't easily stay/become competitive.
The way I see it, Milan will have suitors lined up for years(even as we play poorly). We've seen how many people are interested in investing/purchasing the club. Berlusconi is asking for a lot and it's probably turning away many suitors. But as Silvio ages and his family loses interest and patience with a brand that no longer benefits fininvest, it won't stay like that for many more years(we've already seen Berlu willing to negotiate for partial ownership).
Milan is falling behind its rivals in commercial revenue, but remains popular in places like Asia and South America. Those are big markets that could be worth a lot to a clever investor. If not Bee, some other businessman will come in thinking he can tap into the market that Galliani and company are failing to take advantage of. The major point here is that Milan, despite a negative trend, is simply a couple good decisions away from being a force still. If milans price drops in the coming years(and maybe if it doesn't), I'm sure some rich people will be eager to use the clubs massive fan base to do what Silvio did, gain popularity and relevance.
Lastly, I think as long as serie a remains decently competitive Milan will be okay. And lucky for the club, the league seems to be coming up slowly after a low point. it might take several years before we see a huge turn in milans fortune, but it would take a disaster to truly fall off. Milan remains a few smart investments away from greatness, and will probably remain so for a while. Juventus is a great example. They hit a much lower point than us, and even when they returned to serie a they were in a similar spot(consecutive mid table finishes). They tried to spend their way out, and made some piss poor decisions on players. I think up until last year they were still struggling to get fully rid of some shit players(sound like Galliani?). Then in one season, they changed things up and went undefeated. That growth kept going until they made the UCL final last year. I think Milan could be that, and if those changes don't come that soon, we'll still be alright.