The ability to be able to remember time and date are pretty irrelevant if the computer is connected to internet, also those two settings can be set using easily obtainable references, i.e., your smartphone. Other settings on the other hand tend to be more case by case or unique. If the BIOS doesn't allow exporting them into a file, you would need to write them down or more than a few screenshots, still manual input would be required, even if it's just to load a file.
But TBH my main problem is that depending on the hardware the BIOS default settings won't be able to start the OS, e.g., it might try with the wrong storage.
>We could probably make cmos batteries that last significantly longer with some sorta charge on power on function
Yeah, rechargable CR2032 batteries exist.