There's many reasons long time posters can stop, though I will admit after my first reply to my post in that thread I got out.
They may not be posting or even on the site anymore but they still might be active sharing it, that's how I got here.
My posting has personaly slowed for 3 reasons, firstly, I'm in limbo, I know all I need to to start but have no experience yet, secondly, I have had plenty of time, technology and internet problems going on, lastly, I get scared of posting quite often, and so I don't.