Yes, they were. But it was more than that. The machines were very diverse. Several very different video card options were all in wide use and to make them work efficiently meant low level frame buffer work. Pointers were rare and weird, and again, diverse; bus mice, serial mice and other stuff. Writing a GUI compatible with all the permutations of PC hardware while being simultaneously efficient enough to run from floppies was possible with difficulty, but what value would it have provided? These were 16 bit machines with either no or extremely limited (286) MMUs; just how many processes were you going to be multitasking with your 512K of MMU-less RAM?
DOS was just a program loader, and being just a program loader it was perfectly suited to the PC market. You bought a system with the 'adapter' cards you needed, booted DOS and let some program take over the system, be that Word Perfect, Paradox, Lotus 123 or whatever. That was the real, day to day use case for the PC. An advanced user with a 'fast' disk could bounce between programs in a few seconds and that was entirely sufficient for the vast bulk of PC users. It's also not dissimilar to the contemporary phone/tablet use case.
And I don't remember anyone getting too hung up on the C:> prompt. They either acquired the clues needed to run a few commands or had someone make a .BAT file to kick off their program.
There were certainly contemporaries with compelling UIs, but they invariably cost more and had a vastly smaller catalog of software.