>>fnbr+(OP)
Not a lawyer but those contracts aren't legal. You need something called "consideration" ie something new of value to be legal. They can't just take away something of value that was already agreed upon.
However they could add this to new employee contracts.
>>ethbr1+Mt
I agree with Piper's point that these contracts aren't common in tech, but they're hardly unheard of. In 20 years of consulting work I've seen dozens of them. They're not uncommon. This doesn't look uniquely hostile or amoral for OpenAI, just garden-variety.