unplugmaverick I can only comment with my opinion as an end user.
First, I see updates regularly that incorporate security fixes I would not otherwise have, even on stock Pixel. Certain exploits that affected stock pixels, such as cropped images being "recoverable" and not actually cropped, have not affected GrapheneOS users, in addition to countless other known security holes.
Android car play was added (end of last year or early this year?) to GrapheneOS. I still don't know the digital sorcery that went into making this happen, as this should not have been possible without Google's express cooperation, but its now there. I don't personally use it, but I know it was one of potentially two remaining show-stopping features for regular users that may have prevented them from trying GrapheneOS.
Again, only speaking for myself, I'm not really interested in new features. In fact, some of those new features (like AI integration) is something I hope we won't see in GrapheneOS, or at the minimum, with a toggle to truly disable it completely. There's some cool photo editing magic available on stock pixels, but would I trade that for the additional control, privacy, and security I get with GrapheneOS? Not a chance. Still would like to see a "shake to turn on flashlight" feature like what Motorola phones have, but I've made my peace with that. :-)
Stock apps derive mainly from the AOSP repository (aside from bespoke ones like Vanadium) so yeah, they're not great, but we have better alternatives to use if we choose to.
I'm not sure GrapheneOS will ever be more than a rounding error percentage of users compared to the stock Android ecosystem, and I'm okay with that. Like anything worthwhile, it takes patience and a willingness to learn some new things to use this marvelous OS fully. I am eternally grateful to the GrapheneOS team, as without them I genuinely would not be using a smartphone at all, and I suspect a few of my fellow maniacs here feel the same. :-D
Just my $.02.