Compaq grew nearly as fast as some of those SaaS companies, and was engaged in design, manufacturing and sales of a complex technology product that actually had to work, not just buggy web software. IIRC, they reached $1B faster than any company ever at the time. SaaS and "sharing" economy (really skimming economy) apps are not sustainable, but then as it turned out, neither was Compaq, after they entered into a stupid mergers...
Apple, at least back then, used to hold the record for fastest entry into the Fortune 500. It took them seven years to get there (#411 their first year on the list, in 1983).
They had $583 million in sales for 1983. $1.5 billion in today's dollar. They hit basically $1b the next year, at $982 million for 1984 (in 1984 dollars). Inflation adjusted I'm guessing they hit the $1 billion mark at about six years in business.
I similarly recall that Compaq grew extremely fast. Dell's liftoff followed a similar trajectory (the start was a bit slower, due to how Michael Dell started the company).
Has there been another company since Google that grew so fast? $19mil revenue in 2yrs, then tripling and quadrupling.