In this you are assuming every wage earner will dutifully and unfailingly deposit a weekly sum (which of course will be double the amount of a FICA deduction because of the employer's supplement) into an investment portfolio which they will skillfully monitor and maneuver -- or pay a percentage to some manager whom they are assured is diligent and honest and has their interests in mind. And, most importantly, their investment and its projected growth will be guaranteed by the full faith and credit of the Government against any failure or perfidy of the Market.
Does that adequately describe what you're proposing?
It would not be double because the employer would still contribute.
And the money can be taken as a direct deposit from a paycheck.
People wouldn't have to invest with an investment firm if they didn't want to, they could put it in a savings account for all I care.
And it is not difficult to manage a portfolio even if you are trying to make it out to be.
A balance portfolio with a buy and hold strategy takes only a few hours worth of time a quarter to adjust.
One does not have to pay an adviser hell if you want to invest like Warren Buffett all you have to do is copy his portfolio which you can find on line.
You are confusing long term investing with day trading.