But that's data entry. Development is much less mental labor, and I'd agree with the 4-5 hours/day assessment.
Most people can't actually do this, which is why a lot of people hate math. Math class is dealing with intense focus on a poorly documented thing. Development has little to do with it, but it's the same soft skill.
No you wouldn't. Physical labor varies in difficulty somewhat depending on the type of work, but many blue collar jobs are hell. Forget the anecdotes you read here; they are the exception and not the rule.
That's not to say that coding can't be difficult. But physical labor can be much, much worse.
1) mixed labor (mental, physical)
2) moderate, varied physical labor
3) jobs that are mostly just being present and don't make you pretend to work most of the time
4) mental labor
5) jobs that are mostly just being present but do make you pretend to work most of the time
6) repetitive moderate physical labor
7) repetitive sedentary labor
8) hard physical labor
With 8 being at the bottom mostly due to typically being high-risk and coming with major mid-term harm to health.
The worst jobs are probably done by prison labor and slaves. 8, I would actually classify as dangerous labor, things like how prisoners are made to peel garlic which corrodes their fingernails and teeth.
I like this and think it's accurate. Funnily enough, it gets better if you go on to major in maths. The quality of pre-university maths teaching is just unconscionably bad. (Then it gets bad again as you reach graduate-level maths, but this is because you're expected to be able to deal with that at that point.)
1. You are expected to work 8 hours, while your body/brain is just made for 4 hours of extensive mental work. Afterward, concentration and productivity plunge.
2. Office cultures are rarely made for Deep Work. Instead, you are expected to participate in meetings, communication and presentations.
I think both problems are somewhat solvable, but in many companies, the office culture doesn't make it easy to fit in while solving those factors.