"So Samsung offers an upgrade from Android 2.3 to 4.0? Or are you referring to a Nexus or a rooted phone?"
on many models they offered such upgrade, also lg, sony, and other companies, except alcatel and huawei, they are stuck on 2.3 from what i have seen
if a device can be upgraded or not depends on the amount of ram, amount of internal memory and size of the cpu, those are the limitations that determine the version of android you can use
android 2.3 is around 170 mbs, android 4 is a bit bigger and uses more ram, , it is good if you have 512 mbs of ram minimum and 400mbs of internal storage
i upgraded a lg optimus that was abandoned in 2010 at version 2.1(originally came with 1.6) to cyanogenmod 2.3.7, it is working perfectly, while the hardware specs allow it and you are willing to spend some time, you can keep updated any phone, modified or not
the only version i didn't liked from android is 2.1, it has many limitations that doesn't allow users to do much with their phones and microsd cards
after version 2.3.4 you can do pretty much the same between all the versions released, differences are new features, new keyboard, new artwork(depending if the company uses stock android ui or modified ui) and specific changes on camera and similar stuff, things that you don't care much or you can improve by installing a app without changing the os
it is alot similar to ios, some minor version upgrades offer minor changes but others offer big changes or corrections
"So, no one has ever sent you a picture, via text, that you needed to resize to see better? Seriously?"
no, i don't like text messages(had a couple problems with those) outside live messenger or facebook, when my friends wants to show me a image, they send me a email or the link to the image, maybe we are a bit old school on that
"I know my iPhone is smaller than the gargantuan Galaxy model"
which galaxy, the 4" or the new 4.7"? your iphone is 3.5, some consider that too big and others consider that small, i find hard to consider usable the 4.7" on sIII, i wouldn't have one, i find a bit annoying having a big smartphone, for me any iphone is too big and thick, samsung is big too but alot thinner, motorola droid is razr is thin enough but big too, hard to accept one shape and size, a matter of taste i think
about tablets, it is a market that will disappear eventually, i think that 4 or 5 years, or phones grow to 5 - 6 inches filling the space of most tablets or tablets become dirt cheap, thin, small and flexible as paper so you can carry one alot more easily than your phone
sounds impossible but those technologies are not that far from us, flexible displays exist now, flexible pcbs exist now too and flexible batteries were announced a couple months ago
one will kill another or both will merge into a new market, really portable pcs with real communication capabilities, capable of do anything a laptop can, what most os around seems to be preparing to