it's a well known fact that "password1" is not a strong password, "password2" will get you laughed at as you get hacked, and so it stands to reason that simply incrementing the trailing number will not result in a secure password.
HOWEVER, the string "password" prepended to a strong password (such as a 128 digit random number) does not make the strong password into a weak password, so I theorize that there exists a threshold after which incrementing password1 always results in strong passwords
@aeva all 8-character passwords are just the password “password” encoded with a one-time pad