Ventura docs for M2 Macs in this comment: https://gist.github.com/henrik242/65d26a7deca30bdb9828e183809690bd?permalink_comment_id=4555340#gistcomment-4555340
Old Monterey docs in this old revision: https://gist.github.com/henrik242/65d26a7deca30bdb9828e183809690bd/32c410e3a1de73539c76fa13ea5486569c4e0c5d
Solution for Sonoma: https://gist.github.com/sghiassy/a3927405cf4ffe81242f4ecb01c382ac
It is unlikely for the security reason of air gap. The security is to prevent lost/stolen assets.
If a fresh system is installed, you do not need an internet connection. However, once someone (with internet) signs into Apple iCloud services and enables Find My or the device is registered under an MDM policy, then the option to lock down the use of the machine is lost/stolen is enabled. Legitimate owners can easily disable this remotely or perform the unlock initially during setup if the device really had to be wiped.
In earlier firmware/OS’s, activation lock/Find My (T2 and newer) happened at firmware level and would prevent installing a fresh OS. While I haven’t witnessed it, the Ventura change is reported to also move MDM enablement to that firmware level check. The computers act more like the iOS devices now and if internet is not available, you need to “activate” the new/wiped Mac via USB or other network connection. This check would probably just compare the serial number to find my or MDM enrollment.
Retroactive changes - while Apple could, they have not made these kinds of changes in the past and I would not expect them to start doing that now. Instead they make a change with new hardware and do not allow downgrades beyond a certain supported model. I would expect the M2 Pro/Ultra and beyond devices to require Ventura or newer.
However T2/M1/M2 containing a “BridgeOS” could mean Apple could continue to prevent downgrades, meaning once a newer M1/M2 Mac is upgraded they could prevent downgrades to Monterey, even if that OS is originally supported. I am not sure if a newer firmware restore will allow for an older supported OS; I would assume it should but again it is up to Apple.
I do not have a system to test - most of my knowledge comes from testing and observing the results as well as knowing the theoretical possibilities in technology. Since Apple is the manufacturer, they really could write code to enable or force whatever features/options they want. In older technology, we bypass this by going lower and lower in the system (changing files/data on storage/network), but now Apple is using their chips to cryptographically verify their core code/storage/network communication is secure, so it is increasingly difficult (beyond most normal users) to bypass the system.