15 years ago, I was making $30k a year, and my wife was making $60k a year... We (okay she) had about $200k in investments, but we (okay me) had about $50k of student loan debt.
We both moved up rather rapidly... Me in IT, and her in Human Resources. I spent a lot of time hitting the books after work, and playing with my test domain and test network at home to learn as much as I could. I worked a lot harder back then than I do now.
Every raise, we'd increase our standard of living a bit, but also increase our savings (me, I'd increase how much I was paying each month to pay off the debt).
About 8 years ago, I was making $75k and she was making $100k.... The student loans were paid off, and after taxes, we were living a $90k lifestyle (which is a very good lifestyle here in the MidWest) and saving $50k, plus all bonuses (which were probably another $20k between us).
For the last 4-5 years, I was making $110k and she was making $130k... We were living on our my salary alone, and saving everything she made.
And now we have a paid-off house, plus a million in investments.
We were very lucky to have such good-paying jobs, but we also worked hard to get where we were... The most important thing however, was that we didn't keep increasing our spending to match our income... We realized when we had "enough", and now we're in great shape.
My wife recently quit her job, and it hasn't affected our lifestyle one bit. Since the house is paid off, we can continue to live on my salary alone AND still save a decent amount each year.
Note that we did the majority of our investing during the "lost decade".
A great income is very important, but even more important is to keep the spending under control.