Sure, you can't be fired easily. But what about when it comes time for a raise or promotion? What about when you are interviewing for your next role? It's hard to imagine anyone getting punished for discriminating in these cases, since it's always easy to pin it on other things.

There are lots of things that you're not supposed to be fired for, that people get fired for. Unfortunately, the onus is on the employee, with almost no resources, to prove that the company was lying.

This is not how reality works at all. You're fantasizing.

if you really can't be fired, you surely won't be doing any actual work ever, even if you still get paid.

They fire or sideline you for something else and you never get a job in that industry again.

And if you want to fight it, it's you vs. an army of corporation backed lawyers.

If someone saves you a billion, what's $100m?

What is society but our debts to eachother

We definitely owe them enough money that they could comfortably fill the payment gap to their next job (which might be never, meaning enough money to pay for inflation-adjusted lost income during the entire remainder of their career).

But in the name of pragmatism, it is unlikely that whistleblowers would blow the whistle on a purely economical basis if the reward wasn't higher than that.

Considering that money came out of the fine that their employer paid, I don't see a problem.