At the beginning of the 90p's, I was on the hunt for an alternative to the MSDOS part when, eventually, I tried minix instead .. and that led to replacing it with Linux as soon as it was available on funet. Multiple runs to Fry's to get more RAM and some CPU upgrades later, and I was soon compiling an X/Windows setup on my brand new 486 with 16 Megabytes of RAM .. and about a week after that, I replaced my Quarterdeck setup with a functioning Linux workstation, thorns and warts and all. That was a nice kick in the pants of the operators who were threatening to take away my pizzabox, but it was short-lived joy, as not long thereafter I was able to afford an Indy, which served great for the purpose all through the 90's - and my Linux systems were relegated off the desktop to function as 'servers', once more.
But I always wondered about Quarterdecks' Desqview/X variant, and whether that would have been an alternative solution to the multi-term problem. It seems to me that this was available in 1987/88, which is odd given the articles' claims that X workstations weren't really widespread around that period.