This argument doesn't say anything about the likely pace of such an intelligence explosion. If you are willing to squint, it's not too hard to see ourselves as living through one.

Google has some further candidates. While it can accomplish much more than its founders:

• It uses more resources to do so (in several senses, though not all)
• Google's founders probably could not produce something as effective as Google with very high probability (ex ante)

Owing to the first point, you might expect an "explosion" driven by these dynamics to bottom out when all of society is organized as effectively as google, since at this point there is no further room for development using similar mechanisms.

Owing to the second point, you might not expect there to be any explosion at all. Even if Google was say 100x better than its founders at generating successful companies, it is not clear whether it would create more than 1 in expectation.