This is not good for anyone. I don't want to use another network when I need to use USDT or USDC. I wonder what is the real reason behind this.
ETH on the other hand have one big reason why people still uses stablecoin in there which is to find yield from onchain defi.
Even if USDT and USDC establish their own blockchain, ETH won't lose its TVL.
Of course it will, a lot of the TVL comes from these tokens. If they withdraw them from the other chains, the TVL will go down.