Yes, it was called Wagnis and it worked pretty well - from a technical perspective. I allowed to define a shareware-like experience (14 days for free, then you needed to pay if you want to use the official builds) while keeping things open source (users could still build the apps from source if they wanted).
But in the end it’s a matter of effort vs. benefit. If you do it right, you need to take care of all the nasty red tape such as taxes or maybe even to register a small company (depending on where you live and the applicable legislation). And for a relatively small market such as the one for Sailfish OS, the efforts were simply far too big, so Wagnis was dropped again after two years and the app builds became free of charge again.