I think Paul's point is based on the fact that new technologies are coming along faster, and thus new industries are being born faster than ever before.
And as you say, "Young, fast-developing industries tend to produce rich ecosystems of startups".
These two points imply that the trend is to have many young industries (many more than there are old), and thus many many more startups than big companies.
Further, he mentions how new technologies are game changers. Big companies cannot adapt as fast as smaller ones, and therefore their "death-rate" will be higher.
At the end of the day, I think you're not taking into account the fact that the rate of technological innovation is accelerating. This fact is going to be a large cause of much social and economic disruption (a good thing).
And as you say, "Young, fast-developing industries tend to produce rich ecosystems of startups".
These two points imply that the trend is to have many young industries (many more than there are old), and thus many many more startups than big companies.
Further, he mentions how new technologies are game changers. Big companies cannot adapt as fast as smaller ones, and therefore their "death-rate" will be higher.
At the end of the day, I think you're not taking into account the fact that the rate of technological innovation is accelerating. This fact is going to be a large cause of much social and economic disruption (a good thing).