I think the ball is very much in their court to demonstrate they actually are using their massive compute in such a productive fashion. My BigTech experience would tend to suggest that frugality went out the window the day the valuation took off, and they are in fact just burning compute for little gain, because why not...
If you were a reporter who didn't necessarily understand how to value a particular algorithm or training operation, but you wanted a simple number to compare the amount of work OpenAI vs. Google vs Facebook are putting into their models, yeah, it makes sense. How many petaflops their datacenters are churning through in aggregate is probably correlated to the thing you're trying to understand. And it's probably easier to look at their financials and correlate how much they've spent on GPUs to how many petaflops of compute they need.
But when your investors are giving you more money based on how well they perceive you're doing, and their perception is not an oracle but is instead directly based on how much money you're spending... the GPUs don't actually need to do anything other than make number go up.