Because in the end the profit in these orgs -- or the industry as a whole -- has become profoundly disconnected from a typical industrial production / sales cycle.
A Google or Facebook has a firehose of revenue from clicks, and then must figure out how to internally spend it.
We need to look at the "cream" that rises to the top of this froth.
What is it offering to the world?

And the result is a permanent personal insecurity.
Some manage it better than others.
When working at Google "impostor syndrome" was rampant. Basically cliche. So many people had it.
At what point do we recognize that this is not a "syndrome" or "disorder" but an order of things that the tech industry wants to make natural.
Narcissistic egos at the top, with an army of insecure feeders at the bottom.

Then finally; your github profile, your twitter feed, your blog, your public persona, your portfolio of thoughts & screeds and tutorials.
Even the contributions at work, individually code reviewed, often with intolerable delays that force multiple parallel tracks.
Having to sell each unit of work.
Massive penetration of the employer relationship beyond an exchange of $ for product.
Your whole self must be committed to the industrial project in which your employer exists.

And then the consider the interview -- "tell us about a major project you architected from scratch"; as if in a hypermodern org this kind of self-imposing authorship is a reasonable way to build things, denying both the hierarchical reality of control over creativity as well as the actual realistic necessity for things to be team projects and built from consensus.
Or the flip: "here's a whiteboard, perform something you'll never need to do to prove you're not a fraud"
both pure self-advertising

Now even the most unskilled orgs require whole self supplication prior to admission. "tell us your story" for min. wage job applications
It's terrifying to bring children up in this sales-self environment.
penetration of market into whole mental framework, melting the last old pieces into gold for barter.