Not that many Americans have sufficient stocks to take advantage of the market.
The total amount of money in retirement accounts might be at all-time highs. However, that money is heavily concentrated in a small percentage of the population and limiting opportunities, according to Think Advisor in "Trump Asks 'How's Your 401(k)?' But Most Voters Don't Have One."
While there are different measures of how many Americans have retirement accounts and how much money most people have in those accounts, it appears that overall people are not saving enough for their own retirements.
Only about 45% percent of Americans have an employee-sponsored retirement account and only about 14% own any stocks directly. Even among those people who have retirement accounts, it appears that most of them are not putting nearly as much into them as they need to.
This could make things more difficult for Republicans to reform Social Security and Medicare. Americans might be more reliant on the programs in the future, than many politicians think.