I go aways back, lurked awhile before posting many years/kids ago.
1. If you were once a regular participant at this site and no longer are ... what brought you here at first?
I had just switched from 40K to Fantasy, during start of 3rd ed 40K (whenever that was launched). Played Lizardmen at first. Discovered Empire. Many many average Joe's with pointy sticks only surviving by discipline and tactics was appealing. Searched and found W-E and was instantly hooked by calibre of people and articles. (and fun)
2. If you were once a regular participant at this site and no longer are ... why?
Stopped with GW armies. I had kids and prices were too high. My closest friends who played also moved on. Sold most everything, bought boardgames. Still played B.bowl, D.Ball and X-Wing. Also used my boxes of small space ships to play Full Thrust (awesome generic space battles). Still checked in and commented but slowly died out. Then AoS happened and it killed pretty much all Fantasy desire in me, but then I never played a single 8th ed game anyways. I looked at other systems but nothing has stuck. I'm still friends on other social media with some of the old gits, though.
3. If you were once a regular participant at this site and no longer are, what could bring you back?
I occasionally lurk. But I really have little to contribute, beyond old git grumbling or remember when's. My sons are just getting interested in 40K so there's that. But the reality is, for a casual gamer not looking to spend my kids college funds most collectible miniature games are just not in my pay grade with all my other expenses as a family. In local currency, I could spend $80 for a 10 man unit of crazy fig's, OR, buy 7 Wonders and an expansion. The latter will see the table a lot more (a LOT) than that unit. Not a hard choice. I still love mini's (secretly holding a few still) but I can't ever see myself spending those $ again.
So, I guess, not a lot, b/c its not you, its me