No, they don't probably have programs running that add *no* features to the phone. BUT, the most probably do have programs running in the background that add *non-essential* features to the phone, and thus can be removed safely. And their features added back via Market/SamsungApps, if so desired.
But that "Apparently it doesnt fit though." part.. Yes, apparently that is what they say. Heck, it can even be true, but in that case, I wouldn't be caught confessing I'd be a Samsung programmer. Let's take a step back and take another (yes. bare with me) look at the RAM amounts.
HTC G1, with 192Mb RAM has a GB port and is capable of running it. Search Youtube for dozens of videos. Thus, GB can take a MAXIMUM amount of 192Mb RAM to run on (actual less, because it needs to leave ram for user applications.)
HTC Hero, with 288Mb RAM had ICS running on it, available from xda. Thus ICS can take a MAXIMUM amount of 288Mb RAM to run, etc.
Actually, I just discovered, the HTC G1, the very first Android phone, has an ICS port available with almost full functionality (rotation is quoted to not work). Thus, ICS can really only need 192Mb of RAM to work.
Do you actually, honestly believe that a multi-million company producing some of the best Android hardware and software customizations is incapable of getting ICS and TW working with a phone that has 512Mb or RAM? That TW, on top of ICS requires MORE THAN TWICE the amount of RAM it requires when running on top of GB? TW (with ICS) has a potential amount of 320Mb of RAM to play with in the SGS/Tab/W. We know that 256Mb is enough for whole of Gingerbread AND TW it becomes quite unbelievable to accept that with ICS base TW would take 1.5x the amount the former OS and TW need together.
I realize those are the max amounts of ram in the devices and that free RAM is essential to run any programs, but do the math.
I call BS on the explanation. If it is a ROM issue, the flash can be repartitioned quite easily and the devices in question have more than ample space (2Gb) for everything needed. It may be, that "it doesn't fit", but in that case TW is the most un-optimized, bloated pile of loosely-coded crap out there and everyone at Samsung should be deeply ashamed of ever admitting that. Taking a RAM dump of SGS/Tab running CM9 or the other Alpha3 ICS rom and noting down how much ram it uses is the only relatively real way to see how much ICS requires, but I don't believe for a second that the real reason why Samsung is not updating them to ICS has nothing whatsoever to do with SGS/Tab hardware, other than it being old and not netting Sammy any money from sales anymore.