I wonder what the general reason is that no mainstream mixer really gets into altcoins. Any thoughts from anyone? It seems like it'd be a neat opportunity to differentiate yourself and offer a service to people beyond just the Bitcoin-focused community. And as the altcoin grows in traction, you'd grow with it.
1. Because Bitcoin is fully decentralized
2. Demand! It dictates everything and it happens that the demand to mix bitcoins for privacy reasons is high up there
For Ethereum, Tornado cash tried, but we all know what happened. Also what's the point of an Ethereum mixer if there are smart contract based marketplaces like uniswap.
Besides, there are privacy leaning altcoins like Monero, Dash, Zcash... so there's no point in mixing altcoins if you can access privacy based coins.
For other shitcoins like BNB, SOL etc are centralized. They can even freeze the assets if they want.