@Linox welcome to the PG community!
@creativedaz and @schpengle have summed up the situation well.
Let me just add a few points, as a biased founder of Pinegrow 
We do have a track record of consistently improving the app, from 2014 when we launched till today. In this time span many web dev tools have come and passed. PG is still here, and the level of activity you see is not an initial burst of excitement over a shiny new tool, but a sustained level of activity 8+ years after launch.
That said, our approach protects users from getting stuck with a dead-end tool, even if PG disappears tomorrow.
PG works with standard HTML, CSS etc files. All your projects would still be here, editable and useful. Even our WP builder exports readable & editable PHP code. Only Interactions would not be editable without a visual tool, but could be replaced with plain JS GSAP code with some effort.
Hope this helps!