Questions like these are why I don't love the Password Hashing Competition.
In reality, PBKDF2 is fine. It's not the best thing you can use, in the same sense as AES is probably not the absolute best round-for-round, cycle-for-cycle cipher you can use, but it gets the job done.
The answer for "what password hash should I use" can accurately be summed as "put bcrypt, scrypt, Argon2, and PBKDF2 on a dartboard, and then throw a dart".
In 1PW's case, PBKDF2 is even more reasonable, because 1PW actually needed a KDF, and bcrypt is not an especially good KDF.
In reality, PBKDF2 is fine. It's not the best thing you can use, in the same sense as AES is probably not the absolute best round-for-round, cycle-for-cycle cipher you can use, but it gets the job done.
The answer for "what password hash should I use" can accurately be summed as "put bcrypt, scrypt, Argon2, and PBKDF2 on a dartboard, and then throw a dart".
In 1PW's case, PBKDF2 is even more reasonable, because 1PW actually needed a KDF, and bcrypt is not an especially good KDF.