I manage a small electronics store that also handles three of the major carriers.
That tech support guy is risking his job by even mentioning the "r" word...
Might be, but it's perfectly legal. There was a law which specifically allowed that, and last year it was added to DMCA exemptions as well, after Apple lost legal battle.
If tech loses his/her job over jailbreak suggestion, it can sue the hell out of employer.
Ironically, when debugging issues with in-market devices, many OEMs (when carriers were present in the meetings) have suggested rooting devices with the plethora of tools on the internet.
At their core, there are all ARM based devices (mainly Cortex a8/9s) where almost all of them have 1 of 3 of the most common boot loaders. You could install your own OS on them if you wanted to. Furthermore, many still have the holes/pins on the board for a J-TAG connection... A few try to lock it with 'efi' locks, all of which can be circumvented.
The carriers are the ones who put all that overhead on a phone. Stuf many folks do not want or use. AT&T tech told me I have to root my phone to remove it.
That's only a half truth.
Many apps are developed to either be a showcase of the hardware or the carriers service. The carrier does have the final say, but often doesn't care and the white-labeled app will be burneded in from both OEM and Carrier.
BE CAREFUL what apps you run, many of the carrier provided apps are 'opt out' deals, where if you run the app, you are entered into a trial period which then automatically turns into a monthly paid subscription which is tacked on your bill, unless you specifically contact your carrier and 'opt out'. Carriers love this as they get +30% of that cut and most people don't realize they are paying for it.
I have not tested it, but I bet you could do this on android...
get the android sdk tools and usb phone drivers...
from a shell type
>adb remount
>adb shell
>cd /data/data
>ls
This will list all the 'apps' installed on the device, from here you can just delete them.
> rm com.I.hate.this.preloaded.app (or whatever)