But more seriously, I think you're conflating revisionism and orthodoxy; just because Marxism is changed over time doesn't mean that it accepts all changes.
(And by Marxism, I mean Marxism, Marxism-Leninism, and M-L-M. There are a few smaller tendencies as well within all these broader traditions.)
Yes, socialism includes a lot more than Marxism (and did before Marxism even existed.)
And, no, I'm not conflating revisionism with orthodoxy. My experience has been that people who generally adhere to Marx's views but are not concerned with a narrow orthodoxy of a specific approach tend not to identify as "Marxists", and those that identify as "Marxists" tend to be very keen on the orthodoxy of a very specific interpretation or evolution of Marxism (predominantly, an orthodoxy oriented around Leninism or Maoism as the One True Marxism, though sometimes not.)