It seems like all the 32bit stuff could be wrapped in a container of some sort. Part of the issue, as I understand it, is that the Steam client itself is still 32bit. I don't understand why they are still doing that.
Maybe a bit of "if it's not broke don't fix it." Not like moving to 64 bit would see any real improvement in their client.
Valve hasn't updated their own games but that's a whole a different calculation. Wouldn't be surprised if they never update those to run on Apple Silicon or whatever else they change to in 10 years.