Try watching UGC for a month.
Entertainment is the only industry where the competition has exactly the same product with zero cost of goods and often gets to market sooner.
Try this at home: don't watch anything except user generated content for a month.
And if you think the Hollywood studios earn far too much and are rolling in money, consider this: Google's revenue for the first quarter of 2018 was $31 billion as compared to annual worldwide box office revenue (everything, not just Hollywood movies) for 2017 of $40 billion.
Which would you rather be without? Google or Hollywood movies?
Studios get, at most, 50% of the box office in the US and 20% in China. Since most movies worldwide aren't Hollywood movies, it's likely that not much more than $20 billion is for Hollywood movies which would mean the box office revenue for all 5 Hollywood studios is probably at most $20 billion.