Does anybody ever wonder if all this work is worth it?

I did occasionally. Actually, more than occasionally. I thought about it every time I was studying for an exam where I got to that "ahh fuck it" point at 3:00am when I realized I was probably still going to fail no matter how much more I learned/studied. I just had to fail less than most of my class. So, I sucked it up, and failed less than most of my class (most of the time). Which got me a final GPA somewhere in the mid-upper 2.something, and the right to walk across a stage in front of my proud family. It also got me this fancy piece of paper that I'll probably take out of its tube one day and hang it on a wall. Now I've been out a little bit and feel like I have financial freedom to do pretty much whatever I want (within reason).

And the next 40 years I will be working a job, that I will probably not like.

So, find one you do like, or can at least tolerate. As long as you are a good employee, your employer should want someone with a GT degree. That piece of paper means something because of what all the people before you have done with their lives. Outside of the dreamy jobs, there are still a lot jobs would make great careers. You just have to pick yours.

All my thoughts, all my efforts, in the end no matter what I will end up in the same place, and that is dead.

This is true. But what memories will you have? People say money can't buy you happiness. But, personally, I enjoy making memories via things I can buy with money. So, what's the difference? Travel, entertainment, good food, unique experiences, etc. You also won't have to stress about providing for yourself or a family, if that is going to be your thing in the future. All because you have a fancy piece of paper that says you can put up with a lot of shit, and teach yourself even more.