> on-average double your money
yeah. that is my point: for many people, "double [your spare] money" means going from $1 to $2...
Tech (and finance) workers have always had a surplus of wages enabling a comfortable life and plenty left over for investment. Personally, my 'worst' year investing my wages is when I only saved 50%. Currently, I save 70% of my after-tax income. As a result, "double your money" is a very meaningful number.
But if your wages are closer to the average stagnating wage-growth that doesn't keep up with inflation, double $0 or double $1 isn't meaningful.