Genuinely curious...Why is it that "most of us" it's not? Because you don't like in the US? Or you live in an area w/ limited tech jobs? Or is it that you believe that all 3 criteria is unattainable?
8%...how is that over 30 years unrealistic? That is the historical going rate for the S&P since its inception...
Also I don't know why you threw in the words "post tax" as if it means something for dollar cost averaging. If you dollar cost average the S&P...even in a taxable brokerage account...the only thing you're taxed on is dividends. Your gains compound tax free....If you throw it in a 401k, where the max individual contribution is $19500 then nothing is taxed till you withdraw.
My example of $20k is drawn from a max of $19500 contribution (and hopefully you get employer matching) because ideally you are maxing out a 401k to get the tax benefits.