Assuming 24 bits per pixel, that's 1 Gigabit (128 MB) per image, or ~1,000 images on 128 GB storage.
Dedicated cameras have removable storage and professional photographers will carry multiple 500 GB -- 1 TB+ storage cards, swapping them out through a shoot.
I'll note that the iPhone 15 Pro specs list a 48 MP sensor, which is similar, though storage tends to be as jpeg rather than raw. Compression varies but sizes of 1/2 to 1/15 RAW at high quality are common.
>Assuming 24 bits per pixel, that's 1 GB per image
1Gb, not GB. And in practice it's not that high. Most digital cameras use a Bayer filter, with the pixel count specified as the number of grayscale pixels behind the individual filter elements. Raws are most often 12 or 14 bits per pixel, so about 68MB or 79MB for a 45MP sensor. This can be further reduced with lossless compression. Still a lot for a 128GiB phone, though.