Bruh, you have a cybersec violation on your rep sheet and you couldn't get a job sweeping gravel off a cybersec company's parking lot.

"Cool cyber hacker gets hired by glowie boys" happens only in movies. The risk just isn't worth it. In the very rare cases where the skill is worth the risk, which it never is, rest assured there is a handler team authorised to break both hands, the second the hacker goes off script.

In this situation Google controls the whole setup and is not under any oversight from the customers (i.e. those using the VPN).

In that example of yours they would be a still active hacker whose prime source of income is hacking and who makes way more money from hacking than from said gigs for the "big corporations or the government" and who isn't at all being directly whatched by their employers to make sure they don't abuse the situation.

Would you give a know active black hat a gig doing penetration testing, which they can do from their own place using whatever they want with no oversight and were the possible profit they can make selling what they find in your systems vastly outweighs what you're paying them?

Well, Google continues to have the profit motivation of selling people's personal data, whilst the way black hats turn into white hats is that they can make more money (or at least safer) by helping to improve security rather than break it.

You don't really hire an active black hat to do penetration testing into your system when they can make way more money selling what they'll find in your system than what you're paying them for said penetration testing.

The problem is that Google's core business is still built-around using (and selling, though indirectly) people's private data.