Hollywood has been threatened by TV since TV began. All the innovations (wide-screen, surround sound, 3D, etc) were to keep one step ahead of TV.
For me, seeing a movie has become like going to the theatre/opera now. With premium IMAX tickets, you've gotta book a long time in advance to get the good seats and it costs over $50 for two.
DiF have discussed the changing "tent-pole to regular movie ratio". It does feel like there's fewer quality mid-budget movies being made. Avengers made a bucket-load, so 10 more of those. And after a while they become bland white-bread empty calories. But if the newly emerging markets (e.g. China, Brazil, India, etc) lap them up, then Hollywood movies will become like cigarettes (i.e. past peak saturation in the west, but taking off in the developing world).
What started with Jaws (A & B movie swap budgets) ends up with wall-to-wall teen superheroes.
But Hollywood has bounced back from crises before, so I'm an optimist. I'm not even sure it's a crisis. There's gotta be something to supply the demand for new content. Future content may not be screened in traditional cinemas, but so what?