Comment by dewey

As a business you don't want to serve everyone. That's why many companies after a while raise their prices, even if that prices out the enthusiast market they served at the beginning so they can go further up market.

Often times it does not make sense to serve free users who are often causing more hassle than it's worth. Having a free trial and then either converting users or not makes sense, but serving a user who uses it for a few queries every month ("I check every few months and only do a few searches at most") potentially does not exactly make sense business wise or even warrant the time building that free tier for an audience that's not willing to pay anyway.