This is anecdotal evidence based on my interview experience and conversations with employees, but it was obvious to me that the company had a win-at-all-costs, cutthroat culture. Fowler's exposé certainly took things to a whole new level, but before her report you could see enough from public information (reports of execs' behavior, etc.) and the interview process to know Uber's values & culture. I know of people who were avoiding Uber before the Fowler exposé. I suspect that Uber wouldn't have wanted those people anyways because of contrasting values.
Put another way, I think that the type of people who wouldn't have joined after the Fowler report wouldn't have joined before it. This is now a few years back, though - seems like things may be different now with Dara Khosrowshahi as CEO.
Anecdotally, I know some developers who express disinterest in working for a company like Uber or Facebook. But it would be really difficult to gauge how many or the overall effect - except that over years, maybe, you would see their product suffer as they fail to attract and retain decent talent.
*https://www.washingtonpost.com/business/economy/the-big-prob...
With respect, I think you might be succumbing to a weak form of selection bias (perhaps theres a better bias at play). In my thinking, people who don't work at megacorps have issues with bringing technocratic dystopia into reality (either due to horrific cultural issues at these companies, or by turning humans into labor-machines, either internally, or via externally-developed markets) aren't taken seriously as "opposing voices" in the narrative. No one is debating the fact that you get cheap goods using these practices, but it certainly seems to have a negative effect on overall empathy/humanity, in my perhaps naive opinion.
To bring the point home, if you aren't at Google, Facebook, Amazon, or any of the other gigantic tech companies, you aren't considered part of the "talent pool" unless you have some kind of in, or just deal with the interview process and get one of the roles. I've noticed that because I haven't worked at a "real tech company" individuals at one of the larger Internet companies seem to discount what I have to say, with perhaps what you'd call 'pure tech'-adjacent software development experience at a large investment bank.
I think a huge number of talented people are choosing not to work at one of these firms, Uber as one example, specifically because of moral issues with one of the above issues mentioned.