Earlier quoted context omitted.
Pessimistically, I agree with you. But that lends the question; what does it take to end the Microsoft monopoly on our governments? It can’t just be open document standards. I think it goes further than that; into our schools maybe. I don’t have answers, but it’s a serious question I have.
You could make it illegal to price discriminate on software sales. I.e, if you sell a piece of software at one unit price to someone, you are obliged to sell with that price to anyone who wants it. Obviously that would disrupt quite a few existing business models in software industry, so do not take that as a completely serious proposal.
More specifically, if you can find another place which sells the same model for less, then you get it for the other price.
Thing is, they are the only seller of that model. The vendor has a model X123 for that shop, a model X124 for another place, etc. And that shop is the only one who can sell that specific model. So they of course have the lowest price.
Something similar exists for software: that's why there's "home" and "office" and "professional" and "enterprise" and so many other variants.
So, your "home" version only supports 2 connections at a time, your "office" one doesn't implement a certain function that "professionals" are more likely to use, and your "enterprise" defaults to logging. Even better, with software you can have a unique product for each sale.
All different pieces of software, so all different prices.
Then on top of that, you don't sell the software but software + support. And the support costs can vary.
Which means I think it's easy to bypass your hypothetical restriction.