Yes, and it sucks, but it has been this way for a pretty long time. Jobs was never about expandability/hackability -- the original Macintosh required a special tool to open the case, wherein you could do nothing to it as it had no user serviceable parts. I had never looked before, but it doesn't appear that it even had any socketed ICs: http://en.wikipedia.org/wiki/File:Macintosh-motherboard.jpg , but it did have a proper font silk screened on this board that nobody ever saw. Jobs has used engineering as a means to create the experience -- Woz used the experience as a means to create engineer{s, ing}, something that I owe my love of computers and even my nickname to. :)

That said, so long as Apple essentially has a monopoly on the smartphone experience, it behooves them to control the experience of the device (via third party applications) with an iron fist -- there's very little down side to arbitrary or even counterproductive behavior so long as the experience is maintained. Should ecosystem ever matter more than the device experience, Apple will be forced to sing a different tune, but given Nokia + MS's head start and performance since the release of the iPhone I wouldn't be hopeful.

looks like the ROMs are socketed. and that's the part that you'd be most likely to want changed.

You are absolutely correct. I would say that I'd rather have the RAM ICs socketed, though, especially considering that the first Mac had a meager 128k of it. :(

Could you piggyback RAM by soldering it on top of the existing chips, bending out a single chip-enable pin so it alone wasn't in parallel with the existing chips, and soldering it to a wire? I had an H89 with 64K of RAM; the last 16K was hacked in that way.

Not without switching around the address lines, at the very least.

Yep. The iPhone is a console.