Always_Ask_Questions,
“My mesorah, going back to Rambam, says that Y will only get schar if hashgaha made him unable to earn his own living. Otherwise, the whole reward goes to Z. Otherwise, it is not logical to spuriously decide that one does not want to support himself.”
If you want to invent a polemical “mesorah”, that’s your business, but maybe leave the Rambam out of it.