Depends on how you define it. The indie definition has shifted recently away from definitions relating to record labels/production companies (which would put Mac Demarco in the runnings) and into a definition more closely related to alternative, which has made the label pretty meaningless. So yeah, true, the definition is very malleable.

I disagree that many people listen to stuff much smaller than artists putting in a million. I'm always perusing for new music so I ask a lot of people what they're listening to at the moment - even total strangers. I don't tell them this to their face, but it seems to be a bit of a monolith.