He argues if a better launcher emerged it “would still be of no interest to Steam users” […]
I’m inclined to agree with him too, it would be very difficult to make a better service than Steam

Those arguments seem a bit contradictory.
Is the problem that a better launcher is too difficult to develop or that it wouldn’t be interesting?

Also:

What part of that sounds like “no reason” to give such a service money?

People don’t give Steam any money directly, they buy games in stores, preferably ones that don’t suck.
People also buy on GOG or itch and I’ve never heard either called a superior launcher.

And as for having all games in one library, there are tools for that like GOG galaxy. Steam doesn’t block them so there is no real lock-in problem.

Steam doesn’t stop Epic from offering their users a good user experience, their failure is entirely their own.

We can eat the rich and be sustainable

Do you know how much water it takes to get 1 kilo of rich meat? Not to mention the carbon footprint.
It’s worse than beef.

So far, they are not a thing though.