Well, I don't have a 401K, but an analogous sort of program. But if I did, personally I'd think that was fantastic, it would mean my 401K was fabulously, impossibly successful beyond my wildest dreams of avarice, and the SS was an unnecessary bit of icing on the cake.
Seriously, even a means-tested SS benefit in this scenario (Which is what the muddy-thinking dope is really talking about) would be tested year-to-year, and if it was even possible for this to happen in a given year, it wouldn't last indefinitely and the dope would be right back at full SS benefit as soon as the 401K payout was exhausted or dropped to a more normal level.
However, multi-component benefit systems like FERS for Federal employees joining since the mid-80s incorporate a very modest defined benefit, a participatory plan, AND SS as part of the entire retirement package, and it is therefore unlikely that a 401K itself would preclude SS (though in means-testing, multiple retirements or other earned or passive income might), since the whole concept of the 401K is that it's supposed to complement and supplement SS, not compete with it.
