The iPad clearly isn't for your use cases. The vast majority of people only want to browse, look at photos, read emails and occasionally write some text. For them it's a cheap ($280 for the cheapest iPad) and easy solution.
It's interesting because for a very long time Apple said "maximizing is usually a waste of space" with the zoom button's behavior.
Want to view two emails side-by-side? Use two emails apps, I guess.
I bought her a brand new iMac and it's basically been unused.
Taking away a PC and giving someone a locked down tablet is fairly ridiculous. That'll be just as successful as the "Linux Mandrake replaces Windows XP" rhetoric older geeks remember. You guys were wrong then and wrong today.