The Fenix E is very close to an Epix 2 (non Pro), at least the hardware. So if Garmin would transfer the features of the 8 series to the Epix, probably no one would buy the E, but rather the cheaper Epix 2. So far, so "good". I am afraid that the Epix Pro firmware is closely linked to the no Pro, therefor it suffers from this artificial gap and won't receive updates that it would deserve.
Teeling that my Fenix 7 Pro will receive few or no feature upgrades lessens the value a little bit. I don't like that strategy from Garmin. I think it roots in the price of the F8 that is way too high.