Well you have not spoken with developers years ago.
Most of the were furious as the could not get ProRes license from Apple (regardless if you were well established and recognised company). Those who were lucky had to deal with restrictions, like eg. only Windows Servers OS were allowed to run encoding. It was long and in the same time not that long time ago.
Now it's all past and settled, but use to be very different
Myths are still live though and you hear everyday that you need to pay millions for ProRes encoding license
Of course ProRes looks better, but still iPhone image is what it's (over-processed etc.).
Apple could simply raise bitrate for h264/5 or introduce I only mode and have basically same end effect. Of course Apple wants to promote their tech + they already had ProRes implemented on the chip.
ProRes RAW would be way more interesting, just purely due fact it could save space, but for those who want to shoot movies on iPhone ProRes is good.
If David had such a $ and corpo behind Cineform there would be probably no ProrRes today as from technical point it represent nothing special at all. Cineform still represent most advanced tech (with dynamic metadata, RAW mode with debayering 'in codec' etc) even if it's such an old technology.
As I said- ProRes is liked for other than tech part reasons. It's good, but don't see any reason to praise it so badly. In last 15 years there has been nothing done in terms of intermediate codecs and there is a LOT what could be.