If onboarding wasn't such a big deal and something people needed in order to prove the market exists and there's money to be made, we wouldn't see a good portion of the posts here about it and we wouldn't see so many ShowHNs with people asking for advice on how to make it more clear for their target demographic.
At the end of the day this hurts everyone; dropping users with no where to go and with a fraction of the effort they put into your tool to begin with causes them to question how much they can trust new companies and services. It makes it harder for others to make the case that they are worth using at all, no less long-term.
To turn around and blame users for their so-called ignorance on the matter is ignorant itself. We beg them to sign on with us and then expect them to know that's what they were in for when we kick them to the curb? This problem isn't exclusive to freemium models, either, which is even worse.