Plus, if the ROM chips were socketed, there would still be the option to physically swap the chips if emergency updates were needed without leaving everyone wide open to attack and snooping. Anything has to be better than the current arrangement.
Yes, because having your system vulnerable or down while waiting for the new chips to ship (and hopefully survive the wonderful security and handling procedures of courier/postal firms...) is so much better than quickly downloading software from the makers site and install it.
Code is hard. It's practically impossible (even if theoretically possible) to produce software of a significant size without issues. It could even be that your software ships 100% bug and security flaw free, but someone else finds another way in.
The "old rom chips" did not do anywhere near what is done today. I have somewhere around an ancient hub - 10mbs vs my GB switch. The hub cannot do the speed and despite being made with some very "old rom chips" is not nearly as secure as the switch.
I've got graphics cards with socketed RAM chips and all sorts of other old junk lying around. I have photos which these machines could never hope to display. I've got a 5mb HDD around somewhere (full height MFM), and hundreds (if not thousands) of photographs that said drive could not hold.
Things have moved on and are more complex.
That said, AMD and Intel could make a way for the nastier side of their systems to be disabled if a customer desires, or require a jumper setting on the mobo to enable the communications side of it - lots of ways they could reasonably easily make it so those who want it can have it and those who hate it can kill it. We're probably not even talking cents per board, which they can reclaim by charging the end customers dollars per board anyway.