I saw this discussed a number of times. Every now and then someone comes in and asks exactly the same question as you, OP. If I can generate a random key, what's there to stop the generator from generating an existing private key and then I'll have access to somebody else's wallet.
There was even a guy who was doing it, generating new keys in hope that one of them would happen to be full and posting the results here on the forum. You can find the thread if you spend a while.
As far as I remember he spent a lot of time doing it and never even got a few bucks out of it. I think he got some spent addresses but all of them were empty already.

If it was that easy some of those people would've got a hit on Satoshi's coins already. Imagine getting a Binance wallet or something. Sorry, but your chances of winning a lottery are higher.