Are they seriously abandoning their account to make comments on reddit that will never earn them a cent or collect curator rewards on another site that doesn't yet exist? Steemit is the only game in town (that pays in something other than karma hugs) and likely the payout today will increase over time if the site is successful--so either these people are irrational or full of shit.
If they are the 1.3 billion from Facebook, they aren't likely using Reddit either with its 0.16 billion usership. There are so many different things that users can do on Facebook. Steem is so one-feature-wonder.
And my point is the monetary payouts are not important to most users (because they aren't significant).
The concept of Steem has some upside, but fully leveraging the conceptual model is going to require a lot more development work.