invest it
I don't really understand this.
You make fair points, but this also depends on the exact amount of money won. Suppose you did only win $1 million. That might be enough to live your whole life, or maybe not. If you have a chance to make it last with more certainty, why not?
If you win significantly more, then that argument doesn't hold as much water, but there's also the future past
you to take into account. Suppose you've got kids. Wouldn't it be nice if they could take advantage of the money too? There's certainly some arguments for and against the concept of handing money to kids without them having to earn it, but I'm torn on the issue.
In any case, the money can serve a lot more people than just you, and if you can make it last longer, then it might be beneficial to do so for things that matter after you are gone.
I probably wouldn't quit my job
See, I don't really understand this either. If I suddenly had many millions of dollars thrust upon me, there are far more important things I could be doing than showing up to an office every day.
Changing the world > pushing around pieces of paper
This is also highly context dependent, but in general I agree with you. If I had a McJob, there's no way in heck I'd keep the job if I won the lottery (for several reasons, including denying it to someone who really needs it). In my case though, I would probably stay with my company. I suppose saying I wouldn't quit my job is a bit incorrect here: I really doubt I'd still be programming for Elauwit Networks.
No, instead I'd invest money in the company and try to help them grow and improve. That way I'm creating jobs for people (new programmers, support technicians, field technicians and so on) and helping out those who are already part of the company (improving job security, maybe pay raises that many of them have earned over and over again but could not be awarded due to budget demands).
I also really doubt I'd be working 40 hour work weeks.
No, probably more of 5-10 hours a week to keep up with things and see how stuff is going.
That's sort of changing the world. It's not curing cancer or AIDS, but it's making a difference to those people who needed the jobs, and to the communities where we provide internet and give better service than our competitors.
(I definitely would try to change the world in grander schemes though, such as giving money to medical research. That's just something that would require a fair bit of thought and soul searching though.)