I don't know - I've worked for a startup (in the size/age sense, not in the unicorn scaling sense) where they focused on one market segment (small customers) then got the opportunity to onboard a huge franchise. This required a huge change but would basically make their buisiness stable for X years and allow them to grow into a different market. But they had specific dates that needed to be met because existing provider contract was expiring, etc. etc.

So the product wasn't built for their scale, it took a bunch of invasive changes, dirty hacks, and accepting client specific workflow initially. You can look at that and say "we're lockign ourselves into their workflow" and "we're making client specific features" - but this client literally 3x their revenue year one and increased it a couple times more for extra features developed. And once you have one big client and solve their problems - you can try to generalise and sell to their competition as well.