Between $40 and $60 thousand a year for a considerable time, you have 20 years more to contribute, and you fear that will not fund a comfortable retirement? You'll need at least $3M?
That seems high to me, especially given the free health care you'll enjoy during your retirement. Health care costs (health insurance costs actually) represent a significant cost for retiree's over here.
Do you believe you'll need $3M because the cost of living where you intend to retire is so high, or are you retiring young and living long?
I'm honestly curious. I don't have an analogous situation. I have never had to consider my retirement savings in the same way most Americans do. I have a defined benefits pension from my first career, a defined benefits pension from my second career, and whatever is left of Social Security when I reach eligibility age. I am covered under military medical for life - which really means until I am eligible for medicare. It ain't free, but it is better than most private insurance offers. I contribute to our version of a 401k, but really only as much as necessary to maximize my employers contribution.
We want to retire at 65.
To have a fairly comfortable retirement we reckoned that we'd need around £40k p.a. in today's money. This will allow us to take a couple of holidays a year, buy a car from time and to afford to maintain our house. Allowing for inflation that's around £70k p.a.
Annuity rates are around 5% at the moment so that's why we will need around £1.5 million as a fund. Annuity rates may drop of course and then we'll be absolutely screwed.
Currently in the UK if you have the money invested in a pension, you must use the results to buy an annuity (actually go can get some out as a cash lump sum but the first order approximation is that it all goes into annuity). This may change.
Another thing we need to be alert to in the UK is that although medical treatment is covered under the National Health Service, residential care for the elderly (the accommodation component) is not. That can easily run to £50k pa. Mrs Don and I do not have children or any family who could look after us in our dotage so we have to bear that in mind too. Then again, apart from each other we don't have to worry about inheritance either.