That's absolutely true but this is one of the many things that's "just handled" and abstracted away to the point of invisible with Stripe, etc.

As a founder of my third startup with 1,000 different things to worry about I can't imagine adding this to that list.

You're absolutely correct - even though the IRS released tax guidance and policy on cryptocurrencies in 2014 it's amazing how many people in the cryptocurrency community are unaware or willfully ignorant of the tax implications. When I've brought it up the overwhelming response has been "Yeah right taxes LOL" usually followed by some kind of ad hominem attack or anti-government rant.