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.
They are not discontinuing support on other chains. Tether isn’t even launching this new blockchain themselves. They are only investors in new L1s that use their token as the native asset. It is not in their best interest to be exclusive to a single chain when they are so dominant across many chains.
USDC is also very dominant, especially in DeFi. It would break too many things for Circle to pull out all that liquidity. In fact, they are actually expanding to more chains as Hyperliquid will soon get native USDC.