I could see a webcam pointed at your hand/keyboard to verify input being something legit players would happily opt into.
Not to mention that you would have to comb through all this footage to detect cheaters... It is honestly a laughable solution.
The cheater does not even really need to generate fake video like I've described. Aimbots can be as subtle as the cheater wants them to be, offering <5% precision adjustments which won't be visible on a webcam. Not to mention that half of cheating is just information assistance like wallhacks which this doesn't even cover.
It would be possible to solve if the incentives are not that strong to cheat, but the status game associated with multiplayer games takes care of the "sufficiently motivated part".
It would be possible to solve at a small scale (e.g. at a tournament) by manually vetting hardware and manually reviewing footage.
But preventing cheating at scale against motivated attackers is so expensive as to be uneconomical. The devs will probably try to install whatever malware they can get away with in order to demonstrate to their shareholders that they care about it, but I'm guessing even the devs will be relieved when Microsoft just blocks their kernel-level malware because they know the risks it entails.
Can you imagine your child saying “Mom / Dad I need to buy a webcam to play this game”. Alarm bells will be going off immediately.
Financially speaking, every player needs to buy a webcam to play even a free to play game ?
Do you need a camera of a specific quality ? What if the light in your room is off and the object detection can’t work out where your hand is ?
Do you get kicked from the game because the sun went down and you didn’t turn on the light ?
Can’t imagine the compute resources required to pull this off. The skins in the game will probably have to cost 10x more.
This is just what comes to mind after thinking about this for 2 mins.
Users who are not attempting world record attempts or playing tournaments where money or fame is on the line.. in other words.. 99.99% of the user base will have no incentive to bother with webcam hand recording anti-cheat systems.
They will just move onto another less bothersome game that doesn’t require it, and that game will eat the webcam-required always recording game's market share.
For the ones that are sick of having their games ruined by hackers they’ll angle their webcam down at their hands (or use the app on their smartphone) and join the server that supports it.