I think you have hit the nail on the head when you said Micro$oft.
1. ROMs are easy to copy and burn.
2. How many Gb ROMS do you know of that could hold their Bloatware?
3. And most importantly to MS: With it built in to the computer you would not upgrade it to the latest version.
4. And most importantly to us: You could not load all the security patches.
I remeber when 1k of RAM and Rom was all the memory you needed, now we have 1Tb Hard Drives
at about the same price as a 1K RAM upgrade.