No one likes being poor.
The issue isn't about how long it takes to get good, but how long it takes to extract economic value from the exercise. How good to I have to be in order to make more money doing this than I make right now?
If it takes 10 years to get that value (it does not), then it might not be worth the effort. But I don't think expertise is binary, and the whole 10 years/10,000 hours thing can make people feel like the effort isn't worth it.
There is value to be gained during the 10 (or 50) years you spend honing this craft. And 21 days can create value, if not necessarily expertise.