Someprevious discussion. Looks like there is some info there that's not in your post, e.g. Paraguay also has a Friendly Nations visa which is easier to maintain than Panama's? (Maintaining the visa on a long-term basis could make sense if you're concerned about a disaster where lots of people are suddenly trying to get out >>> countries like Panama and Paraguay make the Friendly Nations visa harder to obtain, while continuing to honor permanent residency for those who have already been granted it.)
Thanks for linking those; I hadn't seen either of them.
I'm a bit familiar with Paraguay's program and should have included it. One likely reason it didn't come to mind is that the anecdata I've come across about Paraguay's has been pretty negative about it working in practice. That said, most, if not all, accounts I've read have been focused on permanent residency as a path to citizenship rather than permanent residency as an end in itself, and I'm unsure whether difficulties tend to arise in obtaining and maintaining the permanent residency or only in converting that to citizenship.
If the linked commenter is correct, to maintain Paraguay's you have to visit every 3 years while for Panama it is every 2 years, although in Panama you can go up to 5 years and then fill out a simple application for reinstatement.
Some previous discussion. Looks like there is some info there that's not in your post, e.g. Paraguay also has a Friendly Nations visa which is easier to maintain than Panama's? (Maintaining the visa on a long-term basis could make sense if you're concerned about a disaster where lots of people are suddenly trying to get out >>> countries like Panama and Paraguay make the Friendly Nations visa harder to obtain, while continuing to honor permanent residency for those who have already been granted it.)