For what it's worth, Panic appears to be one of those smaller indie developers similar to say Bare Bones Software or the Omni Group. I think those are sustainable non-startup software shops that can exist and persist on their own.
Many companies can exist and persist on their own until a behemoth decides they shouldn't.
It's not about "can this business get enough users to be profitable?" it's about "will some huge corporation decide to put them out of business because the cost to do so is a rounding error for them?"
At any point in time, Apple could decide to ship a nice FTP client with macOS, add web language support to XCode and Panic is dust.
