$9bn is 0.5% of AMZN's current market cap, so $9bn represents a daily price fluctuation. They also have $45bn in cash reserves, so amazon could buy 5 MGMs without borrowing or issuing stock.
That's not even a lot! Apple, Google & FB have $200bn, $140bn & $65bn respectively. Dividends don't seem to be a thing, and it's basically impossible to invest this much cash internally. These companies don't have factories to build, or any kind of hard capital investments to make. Even an epic, blue sky cash sink like Waymo isn't capable of burning through their available capital, nevermind credit. Large capital investment at meaningful scale is not part these companies' culture, or competencies.
Acquisition is the only thing they can do, besides buying bitcoin and vanguard. Meanwhile, acquisitions bid up prices and exasperate the scenario further.
Morals and regulatory potential aside, does it not make sense for Tesla to buy and bury one or two major auto manufacturers? Ford is worth $50bn, GM is $80bn. Tesla is $600bn. Why bother competing?
^I'm purposely overstating, to make the provocative point... especially in regards to Tesla, who have no cash and other ways of doing capital investment anyway. Obviously, there is debt financing and other factors that complicate all of this.