i feel like this is a zero-sum situation though, since they're all employees and not owners, which means to a certain degree, the decision by the employer/owner to give more to one employee usually necessarily means giving less to another. to be more pedantic, you could even say the employer doesn't necessarily give less to another but HAS less to give or allocate to another employee.

the situation of course changes if we're talking about part owners as well, then the argument does get a little murkier since it can be argued that improving the overall morale of the lower paid employees will bring about improved productivity and thus eventually lead to improved sales/revenue/profits, which ultimately benefits all the owners.