To suggest that game studios need micro-transactions to "push the boundaries" of modern AAA games is a fallacy. Modern games aren't pushing the boundaries.
Shadow Of War, for example, is littered with busy work and padding. The loot boxes exist solely to remove the need for that busy work, particularly at the end game.
I think gamers have fallen into this mindset of £50 for a game should equate to about 50 hours of gameplay. Everyone wants to turbo their way through a game and then complain that the campaign only took 12 hours so it represents bad value for money.
But if that game has a compelling storyline and encourages multiple play throughs with a different character (mage, warrior, rogue, etc) then surely that game has lived up to the £/hr value that people seem to attribute to a game.
Micro-transactions aren't there to assist publishers with additional revenue to create better games. They are there to make additional revenue so that said publishers can have a mega pay day. That's how capitalism and the profit motive works.
In fact I'd put my money where my mouth is and bet that if micro-transactions were banned from games and stronger labour laws were enacted to protect game developers from the miserable conditions in dev studios that we would get BETTER games all round. I imagine games would take longer to make but would be of overall higher quality with less year to year iterations of the same games.
In the short term perhaps studios would have to adjust to the new conditions and we might see some shorter but high quality games released at various price points, but those Devs and publishers that get it right would grow and reap the rewards.