Interesting post. I have an account there that is 11 years old. I haven't played the game with any amount of seriousness since about 2009. When I first joined, Neopets was already owned by Viacom and driven by commercialism and the money in people's wallets instead of the imagination of the original two owners, Adam and Donna.
To be honest, I think I only played the game for about one year before it went downhill for me. In 2008, they suddenly introduced the new style of Neopets art, only allowing a random few Neopets species and color combinations to remain as they were. In order to keep people around that disliked this change, they added pet trading for the first time, and that changed the entire feel of the site. The community began focusing on the "worth" of pets rather than simply adopting and exploring with pets, and slowly that transformed it into a place of elitists that turned their noses down to people with pets of "lesser value".
As of now, the site is owned by the company Jumpstart (an aged educational company known for the computer games it created in the 90's). Some people thought that change of hands would improve the site and bring it back to its roots, but in some ways it became worse. Viacom had the money to add things to the site, but Jumpstart's a smaller company with less resources. So now the site consists of about five or more different styles of art (new art mixed with the old style you show) and constant cash shop updates. All the events are rehashed each year and with the art of neopets themselves being so unappealing since the redraw (they used to have eight poses for things like being sad and defending themselves in a battle, and now they only have one), there's not really any reason worth returning to the game.
But at one point, yes, this game was unique and interesting.
I remember playing for a short while after Viacom purchased the game in 2006. It was a lot different for sure. the NeoCash stuff was a turn off to me. The game has deteriorated over the past decade without a doubt. I had no idea it was owned by Jumpstart now, though! I owned a few of their 90's educational games :O