Also, while it's financially advantageous to have a two-income family, once you have kids priorities might change. The better choice may be to have a parent at home with the kid(s) instead of utilizing day-care.
You're mileage may vary.
Simply hoarding cash for the rainy day scenario seems like such an awful way to live life. Sure, don't over spend, don't waste, and don't frivolously throw money away, but money is a means to doing things.
While it's true that you can pay for most of those things with a credit card and make monthly payments, may I be so presumptuous as to point out that if you made those monthly payments before you incurred the charges--i.e., put the money into a savings account, even one earning only a quarter of a percent in interest--then when you pay the bill, you pay only 100% of the charges. If you wait until after you incur the charges, and make payments on your credit card, you're going to pay 120% or more of the charges.
Saving money with a near-nil interest rate may be a huge waste of money, but not saving it, and having to pay finance charges when high-ticket items need to be paid for is an even huger waste.
Not that I entirely disagree with you. Dying a rich miser who never enjoyed life is a crappy way to go, just as crappy as being old and broke. As with all things, there's a middle path that probably maximizes both short and long term happiness. :)
It's not a hoarding of cash. It's living on a proper financial diet and it is crucial that you learn it early and abide by it because, when the money does start coming in, you don't get fat and slow, you stay lean and strong.
Also, it isn't all about interest rates. It's about opportunity. Having 100k and being able to borrow 100k are 2 completely different things and the first lends oneself to be much more flexible, opportunistic, and comfortable. (Also, if someone's paying you 3% or whatever, you can bet that their making more than that elsewhere.)
I completely understand what you're saying and there are many people pushing the "rice and beans" stuff. I think that's fine for getting out of a bad spot but not sustainable.
It may seem like an awful way to live, but I wouldn't have it any other way and, so far, it's paid off several times, both financially and through incredible opportunities I couldn't have otherwise taken.
P.S. Many people who "invest" in real estate rent the property, which throws a tremendous wrench in comparisons of simple appreciation.