While I agree that most DSLR shooters are JPG shooters, I would also assert that the overwhelming majority of DSLR shooters don't own a $900+ body. If you specifically look at potential 77D/80D buyers, a large number of them will shoot RAW when they need it or all the time, I think.
It's like, most DSLR owners own cheap kit lens of some kind, but the number of 80D owners who shoot pictures that matter with a cheap kit lens will be much, much smaller, because once you take the dive, you're always looking for little ways to up your game (improve the finished image) by even a tiny bit.
I think DIGIC7 improvements will therefore be a bigger boon to t7i buyers than 77D buyers, generally speaking, though of course, it's an improvement, and all things being equal everyone should be happy for the improvement. I'm not sure what it is with the crazy high ISO... I don't know anyone that shoots with 5 digit ISO lol.