Presumably this is their total net worth. I think this is way more common than people on this type of forum realize. Most will work until they literally can't anymore, then scrape by on social security until they die. I think it's important to keep that perspective.
401k reduces your taxable income when depositing money.
The downsides are a 10% penalty for early withdrawal which makes them surprisingly bad for young people. They tend to start in lower tax brackets, have fewer reserves when unemployed, and face fewer risks from an unbalanced portfolio.
Pay down debt then Roth IRA when young 401k after 40 is often better than defaulting to a 401k, but saving anything tends to be more important than such optimizations.
Surely you need about 20 years?