Yes, and people want their on-the-go computer to be simple to use and reliable, which a software-with-hardware vendor provides. They do not want something that demands tinkering and fiddling with that the hardware-without-software vendors have provided for the last 25 years of home computing.
They tried that and it worked ok for desktops, but people are deciding that they want something easier than that in their pocket.
You want proof? Aren't the most popular smart phones from RIM, Apple, and Palm?
All 3 of those are making their own software and hardware. Coincidence?
EDIT: (You really don't need any more examples than just Blackberries! According to you they're also "making the same mistake Apple made" in the 80's. But don't you think that RIM has proven themselves to be pretty successful by now?)