JB has mentioned V3 of DJI’s FPV Goggles in his recent video
Go to about 12:50 here DJI FPV goggles V3 confirmed (FPV News with JB & ItsBlunty) - YouTube
Mainly speculation at this point as to specs - seems they will be 1080P but no info on framerate. NOT backward compatible with old Air Unit/Vista 
If there’s any truth in the rumours, and generally there is, then DJI do not understand FPV.
FPV users generally do not trade up in the same way camera drone users do. They will have a number of quads which are, in the main, compatible with one controller (maybe a range of receivers) and one goggle. If these V3 goggles are to replace the current V1 and V2 goggles and have no compatibility with current DJI and Caddx Air Units I doubt very much they will sell on their own in the quantity that the current goggles have. I think if anything the current FPV goggle owners would be more inclined to switch to another manufacturer (HDZero) or even go back to analog.
Yes - despite creating the Air Unit & Goggle combination in the first place, DJI seem intent on only supporting their future use with their own FPV drones…including the rumoured Mini FPV…which are expensive and fragile in comparison to ‘traditional’ FPV drones.
I wouldnt be surprised if they only work with the DJI FPV Mini drone/FPV V2 drone and possibly a couple of the newer camera drones. There is no guarantee they will even bring out a new air unit for them. And if they do, what are the chances of the air unit actually transmitting 1080p back to the goggles? Everyone already complains about the bandwidth used for DJI system. If they were transmitting 1080p back to the goggles surely they will be transmitting across the full bandwidth of the DJI systems channels 
With a bit of luck, having the V2 goggles at EOL DJI will just forget about them, leaving those smart hackers that got root access to the V2 goggles to continue to develop features for us 