[strangeattractr]

>Most people are roughly the same in terms of physical and mental capability

I don't think this is true. People vary wildly in how long it takes them to learn and understand concepts. Some people are better at this and so they achieve more with the same amount of time devoted to a particular endeavour. We can be honest about this without feeling worthless. I could devote my entire life to mathematics and I wouldn't become Euler.

Thankfully people vary just as wildly in their affinity for things and that's why we see impressive projects like this. But I aqree with your general premise that seeing other people's endeavours and achievements shouldn't make you feel depressed about how you spend your life.