Obviously kids make this harder and my perspective is certainly biased as my wife and I don't plan on children so our nut is much lower every month than our friends with kids in HS or college.
Depends on your circumstances. 100k with one salary?
If you didn't have kids you would feel incredibly rich. You could pay off your house in five years and feel even richer.
http://ticas.org/posd/state-state-data-2015
The average student loan debt is $27,000. Having four times that amount makes you a massive outlier.
You'd need a lot more data than I have on-hand or care to track down bit-by-bit, but from the number of doctors and lawyers we mint yearly I wouldn't be surprised if 1/10 college grads were well over $50K in debt; MBAs make up something like 10% of graduate degrees and cost around $40K on average by themselves. To me, one in ten is not all that uncommon - student loan delinquency rate more than that ;).
On top of that, it's not "uncommon" for two people who are both surgeons or doctors or lawyers or MBAs to find each other and get married; these people, very much like most of the software engineers I've met, live around their jobs. The people they meet are quite often in their same fields, and have similar financial backgrounds as a result. Two young MBAs? Easily $80K in the hole together.
We in the Bay Area just get this warped sense of perspective because everyone here has to make absurd gobs of money just to make rent, reenforced by the demand for good software engineers being so high. Most of the other people we deal with or interact with are either software engineers themselves or are directly in support of software. We get insulated and siloed from differing perspectives by our monocultured Silicon Valley society.
(And yeah, doctors and lawyers don't usually become doctors and lawyers from the goodness of their hearts alone; they understand that eventually they will come back and get way ahead of their massive debts, especially as the government keeps piling on incentives like debt forgiveness and restructured repayment plans to keep people choosing these avenues of work.)
Do these averages include living expenses outside of dorms? I know plenty of people who foolishly had to borrow to live near campus.
Sure, 100k can go very fast with kids, and it won't make you independently wealthy, but many people manage a "basic life" and even saving some money living on far less.
I think it depends more on circumstances before you get to $100k. If I had parents who paid for school I'd probably be living it up too.
I often wonder if it's just people who have a different concept of what is a necessity vs a luxury due to never having to go without for a significant part of their lives, or people who have just never lived outside of the cities or other expensive areas.
In my case, I lived on the lower end of the income spectrum for much of my childhood, and lived even poorer while building my startup in a low-cost area. So it is with deep experience and sincerity that I say I have no desire ever to repeat those years, nor to inflict such a life on any future young humans.
Ways in which it's not life changing: probably have to live in a more expensive area, which eats into the benefit. Still have to play the office game with people you may or may not like. Still have to save up and budget if you want to travel. You won't live in a mansion with a full-time staff. You still won't have enough money to trade money for popularity if popularity is something you lack and want.
Ways it is life changing: can afford more nutritious and more enjoyable food, which helps make life more sustainable. Can provide better food/clothes/schooling for any children (I have none of my own), which gives them an advantage when they reach adulthood. Can live two or three emergencies away from devastation instead of just one.
Suppose you live in Cambridge, MA and eat all organic food; rent with roommates and utilities costs perhaps 800/mo, subway costs perhaps 100/mo, food costs 300/mo, clothing is perhaps 100/mo, health insurance perhaps 1k/mo. This adds up to 1300/mo, 28k/year. Throw in a very luxurious 5k/year in travel, 4k/year in restaurants and hobbies, and your 100k salary / 67k takehome pay supports you saving 30k/year (more if you use tax advantaged accounts).
Consider a family of four in such a case. Taxes run about 21k/year instead of 33k/year, so takehome is 79k. A 1br in Cambridge runs about 2k/mo, maybe 2.5k/mo for luxury. Subway is 150/mo, food costs 700/mo, clothing of say 200/mo, healthcare is perhaps 1.5k/mo; these run 5k/mo in total, 60k/year. Throw in 5k for travel, rental cars, and hobbies, and you're still saving 15k/year for emergencies.
This seems like a very luxurious life, as someone who's lived it; expensive, and I found it slightly more luxurious than makes me happy. So yes, families affect saving rate, but also provide perpetual free entertainment.
Ugh, for a lot of us roommates == hell. There's no way I'd subject myself to living with strangers again.