Did Valve do anything after initial Steam and Source game ports? Steam client is in dire condition since forever and it’s been years since Catalina dropped support for 32-bit. If they provided 64-bit binaries their games would still be running through Rosetta2 on ARM Macs.
It’s also reasonable to expect that at least Steam client would get ARM update 3 years after first M1 Macs even if they didn’t support their games anymore since Valve makes money predominantly on their cut of sales.