Isn't what you're describing just running a regular company?
You've just described a number of regular business I know. The idea that they're not trying to create competitive advantages is...flawed.
I likely am thinking of a narrow set of "regular businesses" - what came to mind were corner shops, hairdresses, bars or restaurants etc. Even in those cases there are obviously large successful busniesses that do have competitive advantages - but I suspect they mostly get erroded away by competition rather than the business being able to sustain them, and high margins. I would love some counter examples though!
This is a really incredible article about the economics of data businesses, if you haven't seen it: https://pivotal.substack.com/p/economics-of-data-biz?s=r