The investment makes sense even if you think there will be replacement jobs created because nobody wants to be left behind.
If you are spending X on payroll to do Y, and your competitor is now spending X on payroll to do both Y and Z, then they can (a) undercut you on selling Y, and (b) sell Z that you can't even compete with.
(Or, even if you aren't directly going to ever Z yourself, the replacement jobs could be somewhere else entirely. You actually hope this is the case - if there are no replacement jobs, the market for selling Y might shrink, if everyone has less money.)
If you are spending X on payroll to do Y, and your competitor is now spending X on payroll to do both Y and Z, then they can (a) undercut you on selling Y, and (b) sell Z that you can't even compete with.
(Or, even if you aren't directly going to ever Z yourself, the replacement jobs could be somewhere else entirely. You actually hope this is the case - if there are no replacement jobs, the market for selling Y might shrink, if everyone has less money.)