If the MorphOS Team would for some reason totally quit some day (I don't see that happening anytime soon) I'd imagine we'd release the MorphOS free for all then.
My guess is two years.
Really, what is left to do with it? In terms of technology, it stagnated years ago and is way behind just about anything, the only really new thing is making it available on new... old... hardware. Like with OS4 there's a handfull of native software, and if you want to explore Amiga software then UAE is just so much better, and typically faster too - and you can upgrade whenever you like.
Back when MorphOS started, I had big hopes for it, but as time has gone and very little has happened in terms of becoming an alternative to for example Linux, I've more or less given it up, for me it's just a glorified emulator that runs on exotic hardware. Many of the "improvements" and things done to "modernize" it are even the opposite of what I want.
But indeed, the number one reason to not register is this OEM wannabe scheme - those who compare it with OEM Windows don't get it - Microsoft does not only offer OEM releases that are locked to one computer, Microsoft offer several licensing scemes and I can pick one that fits me. With MorphOS it is "take it or leave it", and as devs suggest that it will eventually be free anyways, I'll just leave it for now - in a few years it will most likely be free anyways, and I've been following it for almost a decade already, I can always wait a couple of more years. But perhaps Laire decides to never release it for free, ever - noone knows.
If there was a license I could buy that would allow me to run it limitless on whatever hardware I see fit, I would buy it, even if it costed twice as much - I buy to own, not to "borrow".