Ah, no. They rode IBM's success to their monopoly and even in their first business dealings they had anti-competitive goings on. For example, it was possible to purchase an IBM-PC with DR-DOS instead of PC-DOS, but you ended up paying for PC-DOS and DR-DOS, so it was always cheaper to stick with PC-DOS.

Again, I'm saying that it is hard to look at their success and disentangle their products's merits from their business practices.