For imported labor or those workaholic types, how would you keep those choosing less work competitive? Why would a company not hire someone willing to work full

For imported labor or those workaholic types, how would you keep those choosing less work competitive? Why would a company not hire someone willing to work full time? I’d love to work 3-4 days a week but without mandates I see us ending right back where we are. In short, greed will ruin this idea if it’s left as optional.