Imagine how much more productive we'd be if everyone actually had any reason to give a shit about their company.

First of all, this is very questionable, since data from companies that overpaid/indulged their employees like Google and other tech companies in the past did not really see much increase in productivity as far as I can tell.

Second of all, pressure on wages is different. Hence my referral to minimal wages etc. In a sense, a boss is indeed not incentivised to increase productivity if all the gains go to employees anyway, but this is one special edge case. As you say, a majority of productivity gains come from automation improvements and other kinds of innovation and process optimization, where the incentives do apply.