I am not to suprised about that. The Mac Mini tried to fill a niche that wasn't really there.
While it was the cheapest Mac. It wasn't really a good value. Putting some (rather basic) upgrades in it quickly made it more expensive then an equivalently spec'ed iMac. I think the Niche that needs to be filled is a consumer end Mac Pro replacement. A Desktop PC, with easy to interchange parts that run Mac OS X legally. No small form factor use the good quality but cheaper bigger stuff. In essence a normal range PC around $500.00 that is spec'ed well but not small. For small we have Laptops, the Mac Mini like the Cube tries to get into the area of small PC's which never got a big market.
While it was the cheapest Mac. It wasn't really a good value. Putting some (rather basic) upgrades in it quickly made it more expensive then an equivalently spec'ed iMac. I think the Niche that needs to be filled is a consumer end Mac Pro replacement. A Desktop PC, with easy to interchange parts that run Mac OS X legally. No small form factor use the good quality but cheaper bigger stuff. In essence a normal range PC around $500.00 that is spec'ed well but not small. For small we have Laptops, the Mac Mini like the Cube tries to get into the area of small PC's which never got a big market.