And the more they intertwine, the more they remind you that you're consuming a product generated by a corporation to produce value for shareholders, as opposed to the product of artistic impulse. They become a series of checkboxes to mark off, both on an individual level and as a "universe."
They also are falling victim to the need to escalate the conflict, losing drama as they do so. Like the alleged Stalin quote: "A single death is a tragedy; a million deaths is a statistic."
Of course you can say that if you don't like them, don't see them, but they're annoyingly soaking up funding and expertise that might otherwise go elsewhere. RDJ is wasting his prime playing Iron Man over and over. Ruffalo is a great actor similarly squandered. Etc.
Some people claim that superhero movies help fund smaller movies but I've seen no evidence of that. A24, for example, probably has the best track record of making good movies over the last few years, and I don't believe there's any money flowing to them from any franchises.