Was Guido designing Python for only his own sake, during his time as BDFL? As far as I know, he was not doing that.

Additionally, Guido never had exclusive control over the Python Software Foundation, from what I can see.

If Guido was the only person responsible for the Python Software Foundation, its only board member, its only share holder that the board is responsible to, and was designing Python for the use-case of a single person, himself, and he was soliciting donations, then yes I would consider those donations to effectively be a contribution to an individual. Of course I would.