I don't think only new games attract people. They can bring back old users who may have left if they improve things. And if they bring everything more up to speed with more modern games, (such as no more shockwave or flash games), and add new features, they might be able to draw in new players as well.
They need to do something quick about flash, since chrome is discounting its usage in december.
I think it will be a great success if they put whole neopets' system into a mobile app, but seems like that is a huge project which requires a lot of money and they cant afford.