If you love what you do and are good at it, programming is only somewhat more mentally exhausting than playing computer games all day (and I do relatively complicated stuff: algorithms and numerical math in C++ and ML - don't ask about details, I like my relative anonymity).
The "burnout" happens when there is no reward in sight, or worse: you work hard for many months, produce good results, then your PHB shits on them for political reasons (so you wouldn't get too stuck up), or is just too stupid to appreciate your work.
I'm not a web programmer, and I tend to be very skeptical of much of what PG writes (especially the last few years), but I think independent enterprise is the way to go for the more gifted and hard-working people.
