What AJ2f said, basically. It's all about the compatibility.

It depends on many factors, on which i don't have any influence. Will JJ2 run under future Windows versions? Will it run under sixth or seventh generation Pentiums? Or will Win98/ME run with these new processors? Will future network modes be compatible with the one used in JJ2?
Way too many questions too say something for sure here.
As for other factors, like my so-called "real life" (how i do at university, for example), they will definitely determine the *amount of time* i can spend with "useless" stuff like J2, but they will *never* keep me from playing. Trust me :)

So, *if* everything will be compatible, i will definitely be playing once in a while and check the websites, like the last four years. It's an awesome 2d-side-scroller :)