It's kind of their prerogative to spend their money how they like. If it's anti-competitive then you can hope that regulation exists to prevent that behaviour. As a shareholder you can complain that they will stop this value igniting behaviour. As an investor if you believe this behaviour is irrational you can short their stock and hope that the market is efficient and the share price will reflect the igniting value in their multiple.
As a bystander and outsider it is hard to isolate the value igniting behaviour from the moonshot behaviour. Shareholders love to gut a business of its risk taking and excess behaviour for predictable and inflated margins (and dividends) but the past 20+ years of our megacap companies is that they have continued to "innovate" in spite of all their inefficiencies.
I always have a chuckle when I recall how shareholders tried to oust Zuck for buying Instagram for 1B...
These vanity hires do seem frothy and reminiscent of dotcom style behaviour. But "AI" clearly will be game changing much like the internet was, and who at this stage can say what is worth recruiting people at the forefront of commercialising the tech right now