Now if you're willing to change to a completely incompatible card format like CFast ...
So you never heard of CFast 2.0 ...
Heard of? The entire last paragraph was about CFast. Calling CFast CompactFlash is roughly equivalent to calling SATA IDE.
CFast is not compatible with existing CF cards or readers, which makes it a relatively expensive standard for users to adopt, because no low-end CFast cards exist, as far as I can tell.
Worse, in spite of that added expense, the critical write performance is not that
much better than SD, at 350/450 MB/s versus 240/260 MB/s for SD. And the SD standard currently supports up to 316 MB/s data rates (without further tweaks), but nobody is bothering to build parts at those speeds because little to no camera hardware would be capable of actually pushing that much data yet.
Further, even if the cameras had chipsets that could push that much data, the number of users who would benefit from >12 fps continuous RAW shooting is dwarfed by the number of users who would benefit from the comfort of having a backup of every photo.
Like I said, I'd expect to maybe
see CFast in 4K cameras for supporting RAW. I don't see any obvious benefit to adopting it in still cameras until they get fast enough that the cards are in danger of becoming the main bottleneck. Right now, the SD cards are fast enough to handle 12-14 RAW files per second at 20-odd megapixels in continuous shooting mode without any buffering at all. That's more data than any DSLR actually supports, AFAIK. There's no benefit to building faster cards until there's a camera that actually has to buffer data at those rates.