However, let me describe a few thoughts I had whilst there (not the submitter).
1. Mozilla's mission is just as important as random company making the pipes more efficient for sending cat/twerking/whatever videos. They are a non-profit and are operated as such.
2. They have some incredibly interesting problems that they are working on. From the research team to the browser development itself. Read interesting = hard.
3. They do pay well. I know this as a former intern; also from word of mouth from people who worked there. :)
"You will take a job somewhere else some day and experience great anguish when it is significantly less awesome."
What I'm trying to convey is that I don't believe that anyone need make this compromise. Mozilla is awesome, other organizations are awesome, some freelance gigs are awesome. You can be a software developer without putting yourself through anguish, it's just a matter of priorities.
We work for a company because we think the company can compensate us fairly and those at Mozilla are usually very happy with what they can do (open source projects most of the time). That's interesting. You like your freenlancer, go-everywhere-style, good, but not me.
Idealized city apartment? Half of the people working for Mozilla are remote and the other half spend half of their week at home as well. That's how we work and we make good product.
I like getting a comfortable chair, some snacks and food on a daily and weekly basis. It's like telling people they should all become a freelancer or become their own boss - why work for anybody?
You're a software developer which means you have the opportunity to work virtually wherever and whenever you want. You can write software on a sunny day in the local park, inside a tent in the midst of an Arctic storm, or aboard a boat in the middle of the Atlantic.
A laptop can be purchased for $200 and internet can usually be found free. There is no reason to compromise on a less than exceptional job unless you want to live in the idealized city apartment and collect a sizable salary.