I can't seem to makes sense of your analysis. How does a family of 2 own 2 smart phones and have a child?
A family of two generally refers to a husband and wife, thus two smart phones makes sense. The baby section at the end was to serve as an eye opener if that family of two turns into a family of three. As to how they have a child, refer to your 9th grade biology book ;)
A family of 2, assuming mom and baby (ignoring the 2 phone conundrum), with a home mortgage would have enough deductions to drop their taxable income near $50,000. By my very rough estimate that puts taxes at $10,000 instead of $21,000. Which leaves $1000/month as disposable income versus the $183 you estimated.
With no tax tables in front of me, I took a 30% tax rate. It is a bit exaggerated, but serves to remind people that when you earn 70k per year, you don't take home 70k per year. I wonder why you assumed mom and baby instead of husband and wife. Two totally different tax structures. A single parent could count child care as a tax write off, lowering the taxable income and put in a different tax bracket. If both parents worked and had child care for the express purpose of the mom being to work, they could also count this as a write off, but the OP was making a big deal as to how huge a $70k / year salary is, so I assumed a single earner in the family.
Second, anyone with cash flow problems that spends $433 a month on tv/internet/landline has serious need to reset their priorities. It would not be difficult to cut that in half.
That math problem has been addressed. Working with rough numbers before my caffeine, my fingers slipped. Triple Play by Comcast costs $100 / month for the first two years.
Baby expenses still won't eat up a large chunk of the remainder, but I do not think it is quite as bleak a picture as you paint it.
My son is just over a year old, so those figures are fairly accurate for last year. My insurance company has a max out of pocket of $2,500 / person ($5k / family) per year. Since delivery involves 2 people, we maxed out at $5,000. Due to previous financial situation, we financed it. My wife (who is a stay at home mom) is unable to produce milk, so formula was the only option. Maternity clothes are expensive. Diapers are expensive. Baby furniture is expensive. Baby clothes are expensive. Baby pajamas run $15 / pair. Baby coats are $25-50. Onesies are $8. Sometimes you can find $4 shirts at Walmart.
I'd be interested to see your estimate updated to include deductions before taxes.
I have my employer take out taxes based on 4 exceptions, and we get about $3k back from the feds and $100 from the state.