You guys are working with today’s $1.5K, extended through 20 years to get to $600K in 2030 dollars. You need to start by putting away the cost of premium from 1990. There is just no way the combined premiums since 1990 sitting in a vehicle available to general public would lead to $700K in today’s dollars.
You mean adjust for inflation because if I was starting the comparison at 1990, $1500 would be worth more in 1990 than now…
This is why I used S&P500 numbers as well. With the rate adjusted for inflation (approx 2.8% avg), I got about 6.8% ROI from S&P 500, which does give me more than $600k starting at the equivalent 1990 and the equiv $1500 adjusted for inflation. Using backwards CPI adjustment on inflation of 2.8%/yr, I started with $858.26/month adjusting each pay period by inflation and having an ROI of 10.8% not adjusted for inflation: year 20 gave me $808,413.38 with the monthly contrib at year 20 being $1500.