I think NT was a means to an end (government contracts requiring a "Rainbow book"-qualified OS). It was a long time before the DOS-based Windows OS lost its position as the consumer / business offering. I think that shows MSFT knew what they had in that legacy code and leveraged it for great profit for a long time.
I think the "adults" came in and made a stuffy buttoned-down operating system meant to qualify as a "C2"-compliant OS meant to win contracts. NT doesn't have the hacky charm of the DOS-based Windows versions.
"DOS-based Windows" was not an OS. It was effectively a program which provided a green thread[0] execution model for cooperative processes to execute within and had the reliability one would expect from same.