If I had to render a guess, and its a total guess, is that maybe John Paul wants to continue touring a ton and recording new music, basically striking while the iron is hot because they're pretty popular these days. Joy just had a kid and maybe she wants to take time off/slow down with touring.
You have more personal knowledge of the band than I do, but after reading into that statement, I came to the same conclusion. One of the two doesn't want to go on lengthy tours and have that lifestyle while the other does. I think they both want to continue making music - they just may not tour much.