In terms of hardware, I guess it is possible to get the DJI FPV an upgrade on its EIS on par to the Action 2's (for 1080p at least?)

I know that a lot of DJI FPV owners are complaining on the EIS itself is not enough for producing smooth enough footage like GoPro does.  To tackle this issue, the owners are mounting GoPro on to the DJI FPV.

Not only does mounting a GoPro loose it warranty but also an issue on the weight balance which affects handling.

I guess the would also attracts more FPV done owners to consider buying the DJI FPV Combo (which the sales number seems to be lagging behind other products?)

I agree 100%. I mount a GoPro because of the lacking EIS and the crushed midtones. Since they have a gyro sensor they could just record its data and offer a tool like Reelsteady.

Im seeing a lot of people mounting OA2's now to the FPV.

Any reply from official accounts?