For every game like that, there are a thousand games that shipped, maybe got a few updates, and then they were done.
That meant I could attach Cheat Engine to Roblox, edit memory addresses to give myself in-game cash, and inject whatever code I wanted to everyone else.
Thankfully it was sandboxed so I couldn't give people viruses.
This was probably a good decision because most of Roblox's best games from that period weren't updated to use server functions. It's too difficult.