It also seems a bit odd going from a free software to one where you pay more than Game Maker but then 2 years later don't actually own it.
That's what I also thought. It just makes it sort of greedy.
It's like you first make it as a free alternative for MMF2 and after 10'000 People use this, you just turn this into a subscribe program to cash in. This makes me feel really betrayed, even if the reason would be that you make Construct as a full-time job.
It would be better if you do this like Clickteam does. You pay for the software and when another major update comes out, users owning the old version get a discount. This makes the user decide, if he really wants to jump to a newer version or if he's happy with the software he just has. That's how lots of major software developers do.
But as said, I feel betrayed by having something free and later have to pay to still use it.