They could not control what their employer put in their 401k. Enron only put in Enron stock for the employer contribution. Employees were not allowed to sell any those shares until the age of 50. Even if they left the company.
So I repeat. They had no choice with a substantial part of what was in the 401k.
That is one lousy thing to do to your employees, to prevent them from diversifying the employer contributed portion of their 401k.
And yet, when jobs in Houston were plentiful in the 90s, most Enron employees stayed on, even with a 401K program that raised the eyebrows of the more knowledgeable.
One of those worked with me for a while, in software sales. He said he knew that the restriction on stock sales in the 401K was a disaster waiting to happen, and he bailed after working at Enron for a year.
He also told me that "things like that, that seem too good to be true, generally are." His wife almost divorced him when he quit.
Wrong.
I don't understand why people who know nothing about how 401ks work continue posting nonsense like this.