Support and consulting services are great startup business models. Low cost of entry, generate revenue early in lifecycle thus a strong basis for bootstrapped/organic growth, relatively straightforward sell cycle, lots of opportunity for growth and new market exploitation (e.g. expand from consulting to managed services or SaaS once revenue supports it). I've started several such companies, and it was fun and profitable.
The only people who call a business idea "bad" solely because it doesn't enable "hockey stick growth and massive revenue per employee numbers" are people who's business world view is so constricted that the only possible "good" business is a SV ideal, VC funded, growth at all cost model. That isn't the only way to do it.
A "startup" (according to Wikipedia and most others) is essentially a business in search of a business model (see Steve Blank's work in particular).
A small consulting business is not a startup, it's a small business that already has a perfectly fine business model. As soon as the founder picks up the phone and makes a few calls it's out of the "startup" search phase and is now started as a real business.
It's probably because I'm just a poor, unsophisticated non-SV type, but I never thought I was out of 'startup' phase in the consulting biz until I got my first invoice paid. But even if 'startup' is the hours or days between quitting your day job and hanging out your shingle, I don't see how it invalidates anything I said.
I mean, the word "startup" as referring to a business literally wasn't in use until it was used for silicon Valley electronics companies in the 70s. So yeah, it's got a specific meaning and has had it for the last 50 years.
Some people want to co-opt it to refer to lifestyle businesses and small businesses and whatever else because it gives them better marketing. Most people find that silly.
The only people who call a business idea "bad" solely because it doesn't enable "hockey stick growth and massive revenue per employee numbers" are people who's business world view is so constricted that the only possible "good" business is a SV ideal, VC funded, growth at all cost model. That isn't the only way to do it.