As a long time subscriber, I keep all my issues in three binders that are broken up into sets of 25 (ie. 1-25, 26-50, 51-present). I think you could leave off at 75 issues and that'd be a very respectable stopping point. After all, 2600C was a very necessary purchase back before the net (and even in the earlier days of the net) when there was no other way to network with other collectors and nowhere else to get news.
These days, sites like AA and DP have, for better or worse, taken that mantle and carry it well, with important news spread amongst collectors within minutes instead of months. I'll always gladly subscribe if you put them out, but I wouldn't think any less of you, the great job you've been doing with the zine, or the zine itself if you called it a day.
Everyoe's personal life changes, and projects like a zine take a lot of time. With jobs, spouses and in some cases kids, zine publishers have to make hard decisions (I know from whence I speak, as I had to eventually kill off a few zines I did because of those reasons and because the net made them redundant). Give yourself permission to end it if that's what you want; I suspect that somewhere inside, that's the case.
Clive