1.The "Big Mafia Bankers" don't have control over the blockchain. Manipulating the market and controlling the blockchain are two completely different things.
2.You are trying to build a conspiracy theory about stablecoins being created by Bitcoin haters and fiat supporters. I don't like stablecoins, but I don't believe in your theory as well. The stablecoins actually had a role in the bull runs, which happened in the lest few years. Maybe they are a ticking time bomb, maybe they are a scam, or maybe they are created for the convenience of the cryptocurrency traders.
3.There's nothing wrong with competition. Actually, competition is the driving force of capitalism and market economy. I'm not a fan of altcoins, but Bitcoin needs competition in order to be maintained in a good shape.