By Moore's Law, we can expect hardware speed to be 10 times faster in 5 years and 100 times faster in 10. Even if Bitcoin grows at crazy adoption rates, I think computer speeds will stay ahead of the number of transactions.
Did it increase by tenfold in 5 years? Not even close. Satoshi did not have the adequate data here.
Satoshi certainly didnt do much (if any) analysis of the scaling limitations of Bitcoin.
We need not appeal to authority. Just because Satoshi invented it, that does not mean that he knows the answers to everything.