Sorry, I don't ascribe to the theory that people shouldn't use their observations of industry/society/media/etc and brains to make deductions unless there's a ready-made paper and some stats they can quote.

I came with this hypothesis on my own, without referencing some media industry analyst...

I think the poster probably refers to the basic math of the number of subscriptions/size of the market.

Hitting 0.07% of the market with a free service in a few days is not impressive, do you really need a source for that?