Rug pull scams "pumping up" a new project, nonfungible token (NFT) or coin to get funding. After the scammers get the money, they disappear with it. The coding for these investments prevents people from selling the bitcoin after purchase, so investors are left with a valueless investment.
As far as i know a rugpull is something different that the kind of scam that you are describing OP or i am just reading your message wrong. I don't know. What you describing is a traditional scam that happens not only in crypto but everywhere. People are collecting money from investors and make huge promises in order to get that money but then when they have it they are disappearing and take the money with them. This kind of stuff happens since centuries.
A rug pull is when a new project is launched on a DEX and then, after the trading has started and the token has pumped, the team removes the liquidity from the DEX so it can not be traded anymore, which means the scammers now have more ETH or stablecoin or whatever than before the rugpull.