This isn't how I remember the 90s. I remember Microsoft shipping several versions of laughably bad browsers, while their operating system completely dominated the market. They finally shipped a better browser than NS with IE4, but that has just as much to do with shipping a usable product as it does with NS failing to ship a good product.
That said, in those days the web wasn't yet a big deal, and wouldn't be for another couple of years. I don't see how MS "boosted commerce" at all during this timeframe, either. By the time the web became accessible to the multitudes, and was being used for commerce MS already dominated the browser market.
As I recall, IE3 was passable, not laughable. IE4 was better than usable; as much as I clung to my Netscape Communicator 4, it was better than NS's offering.
IE3 started Netscape's decline, but it really picked up in the couple years after IE4's release (1998-2000).
All that competition, the proliferation of features, the new ecosystems of dev tools, new jobs as companies saw the Internet taking off with MS's weight behind it, the press about the browser wars, being able to click the desktop "Internet" icon on your new computer and see well-rendered and fast websites... to state that none of that actually grew web usage and that MS just took NS's users 1-for-1 is unbelievable to me.
MS made a better browser and put it in front of everyone's face while simultaneously convincing lots of companies to join the fray. The pie exploded.
That said, in those days the web wasn't yet a big deal, and wouldn't be for another couple of years. I don't see how MS "boosted commerce" at all during this timeframe, either. By the time the web became accessible to the multitudes, and was being used for commerce MS already dominated the browser market.