Not /strictly/ nobody - the 3DO version of The 11th Hour was crafted under MPW, using Norcroft C. But yes, CodeWarrior certainly dominated, particularly as the 90s closed.
Obviously, I meant Joel Spolky's definition of "nobody" - Please understand that I'm talking about large trends here, and therefore when I say things like "nobody" I really mean "fewer than 10,000,000 people," and so on and so forth.
Strictly speaking wrt this definition, if MPW had 10M users, it would be a runaway success. But nobody cared, even when it became free.
If you used MacApp, you had to use MPW! I worked for a company where the president read an article about MacApp and as a result made us switch to MacApp. I learned valuable lessons in how to never ship software from that company.