This is so true, in my experience. You hit a roadblock in recurring revenue, not because your product doesn't have enough features, or your team sucks, but simply: your market is smaller than you thought.
Don't take that as a slight to Gumroad either. Building a profitable business from almost going under and now generating close to $1m in annual profits is an incredible feat. But I do disagree with the point that the market wasn't ready (as clearly demonstrated by the success of others).
Two years away from buying back shares for $1 from their VCs?
There's this whole swath of the internet that can support thousands of small businesses that's being slashed and burned by VCs in search of a unicorn. Gumroad and Patreon are both perfect examples. They are both good ideas that are well executed. They are not, however, companies that can extract tens of millions to hundreds of millions in profit a year. They really should be 20-30 employee type companies making a steady couple of million in profit.