So instead we got the 640k barrier, config.sys, interrupt conflicts, extended/expanded memory, 8.3 filenames, segmented memory...
640K barrier is IBMs fault for putting the BIOS at the top of the first 1MB instead of the bottom. Interrupt conflicts, I think you can blame this on IBM too. 8.3 filenames came from CP/M.
EMS/XMS and memory segmentation are FAR more the fault of Intel given these are CPU architecture related.
So...that leaves config.sys(which isn't that terrible really).