For the non-enterprise user, isn't this the scenario established today, with no failed business?

No, I don't think so. All the major internet companies listen to their non-enterprise users. They may not provide enterprise quality support to each individual user, but user voices in aggregate are considered critically important.

not if you have a monopoly. Which is why customer support for most ISPs in the US is so abysmal.

And even if it is just a sufficiently large company, if the customer is not a large payer and the issue is non-trivial to solve, the the cost of losing that customer could very well be less than the cost of fixing the issue.

What I was addressing was specifically the notion that companies pay zero cost for ignoring a customer, or the idea that they believe the same. That's false. Now there's no question there are some customers these large companies are better off without, and there are large and small examples of companies firing customers, or ignoring them til they go away. Nothing wrong with that. All the time on this site we talk about firing unprofitable customers. If you do this judiciously it's just good business. Doing that in particular cases is not the same as doing that generally.