More generally, the problem is how the profits from the saved labour are shared around society. That distribution need not necessarily be distributed in return for labour.
Not really. You can take an Econ 101 class to see that high profits will lead to more competition which leads to lowering of prices... which kills the excess profits and results in higher consumer surplus.
There are scenarios of market failures, where you might have a monopolistic entity but we have safety checks for that too with anti-trust policy.
Yeah I remember when Microsoft came perilously close to dominating the desktop OS market and using that dominance to push their other products, like their suite of Office software. Fortunately the safety checks of anti-trust policy kicked in and they were forced to break up the company to prevent such abuses from happening in the future.
The same thing routinely happens when ISP, TV, and media companies merge:
https://en.wikipedia.org/wiki/Zero-rating#Existing_programs
https://fortune.com/longform/media-company-ownership-consoli...