I'm still playing it. Just because it doesn't have many current releases doesn't mean that it didn't have releases in the past. I haven't played everything the system has to offer.
The Wii for the most part is a multiplayer machine at this point. Games like Wii Sports/Resort/Party are still fun, and I've been having a blast playing various Mario Party titles on it recently. In fact, Mario Party 9 just came out and I should be getting it in the mail soon. So...there's something.
In terms of single player experiences, I'm still working on Kirby's Epic Yarn, which I only bought a few months ago. Never finished Sonic Colors, either. I also have Metroid: Other M still sitting there in its shrink wrap. I have some uncompleted Virtual Console/Wiiware games as well, especially since my brother took the liberty of buying a couple of them during the last month.
As someone who owns a Wii, X360, 3DS, DS Lite, and now a gaming-capable laptop as primary gaming systems, I can't understand why people are so easily "done" with any of them. Again, even in times when new releases are sparse, do people really keep up with the many worth-playing titles at release? I'm way behind and I'm never going to catch up.
I could probably see it back in 2007/2008, but in 2012 it's just weird to hear when people have nothing else to play on their Wii. I guess if you don't play it with friends you might run out of uses for it, but for the average person it seems like there's always something to play, barring personal taste.