It's a perfectly plausible number. 38 million is less than the PS3 did in 2007 (Vgc has it at 37 million, but VGCs total software back then was slightly lacking - the actual number is likely higher).
And honestly, matching the Ps3s 2007 isn't exactly overly optimistic. The Ps3 had an installed base of 8 million at the end of 2007. The Wii u is by Nintendo expected to have one of 12 million.
If anything, the software prediction is low-end.







