I still hate winmodems, they should never have been able to be legally sold with the word modem on them since they lacked the ability to be one. Sure they had a DAC/ADC but were not modems.
Your point with X is valid, it was a nightmare in those days and it was easier to get the right monitor than the right settings.
Dual boot though, I would bet dollars to doughnuts was the hardware itself or the DOS install at fault.
So yeah, excepting the modem (which were expensive) you could run a ripped off version of Windows cheaper, but that was at the same time that people were installing Linux machines whose reboot cycle was more likely determined by the power supply than the OS.
Today, I had to reboot Windows 8.1 so that it could open an excel document...