Nonsense -- what blew WordPerfect from the market was the appalling version of WordPerfect for Windows they relesed around 1992 that was so bug-ridden it was unuseable; I had to use it for a 2 day course in 1992 where it crashed literally every 5 minutes, even
when you weren't doing anything complicated.
I remember it well.
WordPerfect mistakenly believed that their word processor alone was enough to keep the world using DOS. By the time they realised that Windows was the future, they had to rush out a half-baked weird semi-GUI mutant that I had great trouble getting to start
Much of Microsoft's success is down to the howling foul-ups made by the competition. (IBM not having a clue how to sell OS/2 and Apple beleiving that they could flog a desktop to Joe Public for a the price of a car.)