Personally i wouldnt think the site is dying, Most web Adoptable games are like this. The only active ones are Flight Rising (and the infamous Pokefarm q, ew)

As the original poster mentioned, they don't have anything active to do on Pixpet. Pixpet is too passive for most people's tastes. There are only three arcade games and adventure can get repetitive. The only way you can progress is by waiting, and Speed up potions (known as Super potions, but eh) are only used in the spur of the moment, when you just can't wait. I don't think anyone really buys those because im order to actively progress you would need lots and lots of potions, which is an overall net loss; You're better off using that money to buy a bigger and better house!

Edit: my last paragraph went a bit off topic, oops.

Anyway, Im sad to see you being unhappy with your experience on this site, but this site is meant to be played passively, something to do when you have only 5-10 min of free time.
If you wish, you could post your pets and eggs off-site. It's how discovered pixpet, i clicked on a canisqua on someone's signature! Sites like these need their users to advertise! If you play any other Adoptable game, i recommend posting your pets in your signature there.