I think you are mixing different things together.
Pump and dump is a market manipulation practice. Even is highly regulated markets, such as the stock market, there are pump and dump schemes.
Bitcoin scarcity is totally unrelated to market manipulation. Scarcity makes it more valuable, but what would make it resilient to manipulation would be regulations, what bitcoin lacks.
Who can forget Elon Musk playing around, saying he was going to use bitcoin as a payment method in tesla, then he suddenly changed his mind? This is market manipulation
You're right pump and dump coins are usually from those altcoins that are newly created whenever there's hype or just something trending on the internet and they create some coins along with it, just like what happened to Squidgame tokens which were one of the biggest pump and dump science has ever happened in the crypto market and bitcoins has nothing to do with it just like any other coins when they want to scam people with their scam strategy to create a hype then dump the coins when they see lots of people already bought it.