You can do a one-time purchase, IIRC it was ~$45 around a month ago when I purchased it. I wanted to buy outright instead of go the Patreon route.

As far as abandonment, I had a fairly subtle issue with it shortly after starting to try it, and on github I opened an issue and got help troubleshooting it in a day, we were able to identify the problem and there was a fix in the build the following day.