Re: Older artworks- You can re-set your artwork's front page date in the Art Tracking grid, so that an older work reappears on the front page. I think there are some rules though, like you can't have the same work appear on the front page more than once every six months. It probably mentions it in the Help Centre somewhere.
I've "re-front-paged" a few works, during periods where I've been going through art blocks and had nothing new to post for two or three weeks. It helped bring people into my gallery even though I wasn't super active at the time. It's not something I do a whole lot, but I hope that explains why it happens!