24 bit scanners might have a dynamic range specifications near 2.4, needed for photo prints. 30 bit scanners might be near 3.0, needed for negatives. The best 36 bit scanners might approach 3.6, better for slides. For sure, they can't be more. And of course, all scanners are not equal, some will have higher dynamic range than others because their electronics have less noise.
Price is definitely a factor.
The greater dynamic range extends the signal into low black levels where the noise is. To be effective, the electronics must be improved greatly to reduce the noise. The hardest problem for the scanner is the black end, density values up near 3.0. One good reason is low level signal and noise. But the big problem is the necessary logarithmic mapping explained below.