I have to assume they're targeting 30fps because that would be using all the bells and whistles like raytracing and running at 4k on the consoles; which are unlikely to be able to achieve 60fps or higher with all that shit on.
And, as they have done with literally every single GTA since 3: It likely won't release on PC at the same time. It will come 1-2 full years later and when it does, will have more features and run at a higher frame rate.
You mean it won't happen again. Netflix's goal was never to be good. It was to disrupt the industry. And they've succeeded; which is why everything sucks and piracy is a better option once again.