You might point out that some individuals pay more than the average, but I don't see a reason to single out the woman who needs daycare over the salesman who needs a custom suit.
As a practical matter, the personal exemption and standard deduction are high enough to cover the salesman's custom suit or commuting expenses, etc. Where it really falls down is with daycare and similar expenses.
I also don't think you realize how much a custom suit costs. It could easily be way out of the ballpark of the personal exemption.
Much like college tuition increases, a government tax break merely means the suppliers will all increase prices to adsorb the new supply of money. Its basic supply and demand, you have a supply of more money, so we'll demand it. A govt tax break has no impact on the standard of living of the population, its a give away for the industry it applies to.
Also DCRA is a complicated tax mess where its incompatible with some other social engineering child tax credit scheme, causing all manner of annoyance and confusion. That's all I remember of that detail, at least 5 to 10 years ago at the fed level you could put pre-tax income into a DCRA OR not pay income tax on some small subset of childcare expenses but obviously you couldn't double dip and apply both credits to untax your untaxed income although the paperwork made it easy enough to accidentally try.
E.g. if you're in a business, you get to deduct the cost of employee salaries. The portion of your revenue that goes to employee salaries isn't a benefit to you in any way except as a necessary part of your business. If you didn't have the business, you wouldn't have that expense. Allowing the deduction isn't a "tax break" but is rather necessary in order to properly define "net income" as distinct from "revenue."
Day care is similar. It's a necessary expense of going to work. The portion of your salary spent on daycare isn't a benefit to you in anyway except as a necessary condition of going to work. If you didn't go to work, you wouldn't have that expense.
Sure, the ratios can get quite a bit better as the babies get older, but you're still talking about rates that seem more appropriate for the 3rd world or the 19th century with a servant underclass than about rates that are appropriate for the professionals that many early childhood educators are.
Also if you think early childhood educators make more than minimum wage, well, you must not know any.
1: http://www.livingin-canada.com/salaries-for-early-childhood-...
The minimum wage in Canada is about $10, +/- 50 cents depending on jurisdiction.
Imputing taxes is a can of worms, but it doesn't help your position. If such taxes existed, you'd be taxed on the fair market value of the child care duties performed by your wife.
I decide to swap kids with a neighbor during the day. My wife watches their kids, they watch our kids. We pay each other 40k a year to do so. I would then be able to deduct the 40k as a child care expense, but I would also have 40k additional income. The net result on taxable income would be zero.
In a lot of ways, that makes perfect sense.
The fact that couples choose to have two spouses work is irrelevant. Daycare has no consumptive value either way. A company can choose to hire a separate CTO instead of combining the role into another position. They are entitled to deduct his salary anyway, and companies that don't hire a separate CTO can't complain about not getting a deduction too.
You can't deduct the full amount of a steakhouse lunch as a "cost of doing business." You can deduct 50% of the amount. And if you have a significant number of these deductions, don't be surprised when they are challenged.
As for the suggestion that daycare be a deductible expense "as a cost of being able to work", I think you'd have more success arguing for structural tax reform than new deductions targeted to a specific group of people. After all, there are a whole host of other items that aren't currently deductible, such as regular commute expenses, that one might argue are "a cost of being able to work."