I doubt the b450 are gonna list higher than 3200 odd because ryzen 2000 not officially supporting it.
I'm waiting for the Tomahawk max for the bigger bios but....
https://www.msi.com/Motherboard/B450-TOMAHAWK-MAX/Specification
For AMD Ryzen Gen3 (R5/R7/R9)
2667/2800/2933/3000/3066/3200/3466/3600/3733/3866/4000/4133 by A-XMP OC mode
I assume the main reason is for the memory support? Is there any other real reason to wait?