I am personally of the opinion of:
1) The substitution of 401ks for actual pension plans was a faustian deal orchestrated in order to further enrich the plutocrat caste, by eliminating any direct obligation to their employees after they retire, (and thus further reinforcing the notion that employees are not investments, but instead disposable like tissue paper), while pulling a slight of hand trick that they (employees) are now shareholders (assuming they buy stock options in their 401k plans), and thus benefit from the very policies that eliminate the assured income streams pensions provide later.
2) The reliance on 401ks in the market to provide for the elderly, is unreliable at best. The assertion that it keeps with inflation is farcical-- not that it does not do that thing, but that it somehow retains its value during times of economic uncertainty (which it most certainly does not), and is when these populations need reliable income the most. It is a terrible vehicle to assure the providence of those who have done their time at the grindstone, and need to be taken to pasture. (and not the goddamn abattoir.)
3) Wages, which are required to pay into a 401k, have NOT held steady with inflation for the better part of a century. Even with employee matching, employees cannot afford to have that much of their pay diverted to the 401k, and this is done (low wages) precisely to further enrich the plutocrat class.
So, excuse me while I look very disgustedly at the whole damn notion of 401ks.