All my GTD attempts totally collapse in weeks
One part of GTD works for me really well and I've been doing it for maybe five years now. That's gathering all inputs in small number of places (these are one paper folder for physical objects, one folder on my desktop, and one folder in my mailbox - reducing this numbers seems rather pointless).
Then I have a reference system (one for paper stuff, and one for electronic documents) which works reasonably well.
Unfortunately every time I try to do the rest, it just collapses. I'd go through my inbox, get rid of most items by either trashing them or moving them to a sensible reference place; then turn the rest into projects and next actions. And invariably during the next few days or weeks I do a lot of small things, progress on a few stalled projects, and every system I tried turns into such mess that the only solution is moving all my lists to the inbox and starting all over.
I've tried paper lists, and some electronic systems, it fails too quickly either way. Part of the reason might be that far too many items are not clearly actionable - they're in all shades of "waiting for but keep track of", "someday maybe but potentially very useful", "I thought this was a project or next action, but due to some inputs it needs to wait now" etc. And even when there's reasonable clarity, the volume of it all makes it difficult.
So what kind of gear/software (I'm on Mac, that limits my options somewhat) should I try next? I know it's not purely gear-problem, but it's a big part of it.