This is not really true. This is easy for us to check since many of these companies are publicly traded and are required to report their financials.
As one example, EA claims in their public filings that EA's cost for AAA game development has decreased over the last ten years (roughly $300 million less dev costs per year today, inflation adjusted, than they spent in 2009).
> AAA budgets, $60 titles, and no microtransactions or subscriptions is absolutely a 'pick two' scenario.
It's not -- and again, we can know this for a fact from their public financials. EA claims their traditional AAA games (sales only, explicitly excluding any microtransactions or lootboxes) carry roughly 60% profit margin all on their own.
They definitely don't need the extra gambling revenue, but it's obvious why they want it.
It's third installment, Dead Space 3, was slated to sell minimum of 5 million copies. With less than 5 million, EA decided that it's not going to be profitable enough. It also had microtransactions and DLCs on top of those required 5 million copies sold.
Who's greedy here?
Where I am, AAA games used to cost €40 at the top end. Then €50. Then €60 and now I see them for €70 (more if you buy bullshit deluxe editions that give you extra skins or somesuch; more still for collectors editions, but they've always existed).
So, at least where I am, I'm not seeing it staying "rock steady for decades".