I think the primary inspiration for Bitcoin was Adam Back's Hashcash, not Wei Dai's b-money.
1) Satoshi's email to Wei Dai indicates that he had not previously read the b-money post:
"I was very interested to read your b-money page. ... Adam Back (
hashcash.org) noticed the similarities and pointed me to your site."
2) The Bitcoin whitepaper cites b-money only as support:
"transactions must be publicly announced [1]"
3) The Bitcoin whitepaper cites Hashcash by name:
"a proof-of-work system similar to Adam Back's Hashcash"
4) The format and style of the Bitcoin whitepaper closely matches the Hashcash paper. In contrast, the b-money post is plaintext.
http://www.hashcash.org/papers/hashcash.pdf
NB: The Hashcash paper cites b-money.
5) Satoshi's first post cites Hashcash by name:
"New coins are made from Hashcash style proof-of-work."
https://www.metzdowd.com/pipermail/cryptography/2008-October/014810.html