They said they'd probably have to if Fedora removed support for 32-bit packages, which was a proposal to the Fedora Community (who rejected the proposal).
Long-term, I imagine Valve will have to bundle a 32-to-64-bit abstraction layer, like they already do with a win-to-linux abstraction layer (Proton), and are preparing to do with an x86-to-ARM abstraction layer.
Distros do not want to each duplicate the work of maintaining 32-bit support for all eternity.