I think the point is there are many "startups" with similar revenue and growth to Linear that never become profitable. I don't think Linear qualifies as a small business and I don't think they're scaling less quickly than someone in same market with more funding and less profit.
To me a startup hasn't found a product-market fit yet. That's the whole point, they're trying to find a way to get profitable. As soon as you are profitable, then you are a normal company.