Excellent advice, it needs to be said. I overstayed my welcome at one job for several years - I finally moved on but should have done it sooner!
I wrote a thing about how you owe it to yourself to quit the bullshit & move on because, "No one will reduce the bullshit in your life besides you."
I liked the article a lot. Early on, you write something to the effect of "This may be an over-privileged thing to say..." You're right to point that out. But I'm glad you kept writing. Because being in a privileged situation doesn't mean we can't keep reaching and striving to make our lives better.
We should reflect on all of the fortunes of time, place, and circumstance that have come together to have a job that has so many benefits, but that doesn't mean we have to settle for "good enough". I think, for a lot of designers, they have some inherent guilt that they're doing what they love and getting paid for it. That guilt prevents them from taking chances, asking for more money, or starting out on their own. They feel like that shows a lack of appreciation for having a great job. But if you think your life can be better by asking for more, by all means, ask for more.
Don't be a dick about it, but keep reaching until you're not only comfortable, you're happy.
YES. Totally agree. All of that.