Even with the massive user base, I can't see the Wii chugging along like the PS2 did, which is basically saying the Wii won't have 3-4 more years of cheapie ports and cash-ins.

In actuality, the Wii's existence is what kept the PS2 viable in stores until now. Most of the games still trickling out for the PS2 were Wii ports (and a few PSP ports). The Wii doesn't have that advantage now.