So Bitcoin (BTC) was just the test run for the next Bitcoin
exactly
My opinion:
Satoshi Nakamoto is one person and will come back with the improved Bitcoin and with another pseudonym. He will not try to advertise or sell the new concept because he knows that the Bitcoin and crypto community will use it as it will be good.
what about those altcoins and tokens that we saw ? arent they the new bitcoins that you are talkin about ? i think they are because btc was the first crypto coin that is introduced and we can say that it was a test to see if it will become a succesor but it did and after that , altcoin and tokens suddenly appeared but those devs are i think not satoshi or related to him . they only get some idea on the concept of the orginal bitcoin and they make a little change on thier own coin .