Sorry, the 90s were a real time, and the ambition to replace the desktop OS was already there, as per the ~1995 Bob Metcalfe quip (popularized by Marc Andreesen) that the Netscape browser would soon reduce Windows to "a poorly debugged set of device drivers".

There was a bit of a lull in progress in the mid-2000s, after the fall of Netscape Inc, until the rise of the mobile app threat you mention.