Your saying two separate things there.
HE does allow YOU to develop anything you choose to.
HE did NOT have a native ring integration, when you bought it nor to my knowledge has stated that it is "on the list" of upcoming features to entice you to HE for this feature....
I would assume why they haven't made such announcement is like I previously pointed out for 2 reasons.
The cloud based device wouldn't be a priority of limited development resources for a localized platform.
There isn't much more features a "native integration" can offer more than what IFTTT (which is already integrated) already does offer to be using those limited resources for.
I would venture to say just as many people have Roomba robot vacuum cleaners as have Ring doorbells, and the same scenario applies to that and other cloud based devices as well for dedicating the limited resources.
At one time there was a Nest native integration attempt, but now Nest decided to totally change their "partner program" so now that time spent there was wasted would need redone. Reliant on other manufactures and/or cloud seems to be the opposite business model of HE.