"As is also the case in many company 401K programs, until recently, stock holdings from the company match could not be transferred into other investment options until the employee reached age 50."
That's precisely what I said.
You can transfer your own contributions whenever you wish - the free matching stock the company can give you if it wants to give you free stock cannot be transferred until it vests.
If your retirement plan is based not on your own investment but on the hope that your employer will give you enough free shares to enable you to retire, then you don't actually have a retirement plan.