Azure revenue is growing at 39% year over year. If Microsoft can sustain this growth, in four years Azure will be ~3.73x its current size. This is of course very difficult, but you really don’t need a deus ex machina to hit 4x growth under your assumptions.
The issue in the late-90s was all the investment created a lot of real revenue for telecoms and other companies. Even though there were a lot of shenanigans with revenue, a lot of real money was spent on fiber and tech generally.
But the real money was investment that didn’t see a return for the investor. The investments needed to have higher final consumption (such as through better productivity or through displacing other costs) to pay back the investment.