> What argument can one make when the burden of proof is to show cultural regression?
Maturing industries lose diversity as they trend towards optimization. This is something that is bound to happen regardless of industry. America has far fewer automotive manufactures than it 100 years ago and diversity has suffered; same goes for soda manufactures, etc.
With about any industry, you can gauge how mature it is by the diversity it has achieved. It starts with one or two who demonstrate the viability of the market, then there is an explosion of interest as many people break in, trying different strategies to gain market share, then the few winners consolidate the industry. Sometimes, the big players rest on their laurels and an upstart takes hold, but they are usually acquired by the establishment or their strategy is emulated then they are crushed by the inherent resource imbalance.
The big movie studios know what works and they are going to stick to that. Occasionally a Pixar will come along and disrupt the market, but when that happens, a Disney is going to step in and acquire them and change or adapt their formula to prevent another upstart.