UST has had a bigger MCAP than LUNA prior to the depeg, and was unable to be supported as a result.
However, USTC has had an MCAP that was 5x smaller than LUNC in the past few days. With proposals to burn UST that was kept for incentives, etc. it may be easy for USTC to return to it's peg (same MCAP as LUNC), that target would be $0.1 for USTC based on the current LUNC MCAP