Mark thinks "buy and hold" and "investing your cash at all times" are wrong. His contention is that the market is not homogeneous anymore, with billion dollar hedge funds and advance algorithm programs woven into the fabric of the market, the retailers become the victim most of the time. He doesn't see any advantage for the everyday retailers now.
He stated that if you are not hundred percent sure, keeping your money in cash is the way to go. He thinks diversification is for idiots, because you cannot diversify enough to know what you are doing. Only enter into a position when the market has tanked tremendously and after you have done your full indepth research beforehand.
The interviewer asked what should the average person do with his/her money then? He advised them to first pay off their credit card loans then buy discounted items in bulk to beat inflation. With the bulk of your money in cash, you can sleep easy and hence reduce your medical expenses that way.
It is interesting to know the different kinds of philosophy individuals have on investing. This will make for a very polarized discussion, as I am sure, both sides of the spectrum have their own success stories to affirm to.