Delivering a quality free product to get companies to sign for the expansive one when their needs increase is a very common marketing system, and allows to keep control of the market despite being vastly out of price. Works for desktop app, mobile app, web services, ... I say this as someone who once had to sign for the full version for a web property I was working at.
This is a matter where people are quick to over react so let's be super clear: I am NOT saying the limit is placed at a reasonable level, nor that companies absolutely need to have the paid version and can't extrapolate enough from the free version data (they absolutely can), nor that Google isn't majorly benefitting in other way than full version sales (they do).
What I'm saying is that "the base version is free and the full version is paid" is a very common thing that doesn't by itself mean anything nefarious is taking place.