> > so what happens when the engine becomes retired?
>
> Ask Construct Classic ;)
Not sure if it will be open source like C1 though.
There is quite the risk of C2 (community edition), turning out to be more feature-rich than C3.
On the other hand, if people really cared that much about native performance through native exporters, 3D and all the other highly requested stuff, C1 wouldn't be as abandoned and broken as it is right now.
Well, I was meaning more like Scirra will bury it on their main pages, drop its forums to the bottom just above Construct Classic's tiny section, and likely stop selling it at all to promote more business to C3.
That said, Construct Classic was built on some proprietary UI library that is deeply ingrained, so building for it required purchasing that library (at the time, possibly open sourced now?)
There was a Construct Classic community build going that improved on Construct Classic vanilla, I think 
R0J0hound was doing the builds for it as he had the library.
However, I think the people who really cared about those features simply moved on, like we did to Unity, because we are after all an audience of game developers who prefer not to code at all, so suddenly picking up C++ to continue an engine that even its own creators abandoned is not ideal.