While yearly admissions in the US and Canada have stagnated (and declined slightly) over the last 15 years (which is what he talks about in the video), money from overseas audiences have increased a lot in the last decade. Mojo's yearly list has the top 50 movies making around $7 billion a year in 2002-2005, then it started rising fast up to $15 billion last year. And while yes that does ignore the increasing inequality among movies, it more than makes up for the higher budgets as long as each studio is getting their share of the big hits so that they all can make up for their big bombs.
I think WB is the most likely to go through a big change in the next couple years because they're late to the superhero game and they don't seem to be able to keep their budgets in line with the potential of the product they're putting out.
I think overall though any changes to the industry will be very gradual and that movie theaters will continue existing for a long time to come in large part because the overseas audiences will keep the tentpoles rolling which justifies large marketing budgets and will keep even domestic audiences showing up for a couple big movies each year.
Personally I think the internet is what is for the most part causing the bigger highs and forcing the mid-level hits out. People everywhere "congregate" around the current thing that's in, and no one wants to be left out so the hits get more attention from everyone, and time/attention is limited leaving less for everyone else.
Anyway, that's enough rambling for now.