You are absolutely correct. It all centers around discipline. As Will Rogers, the cowboy humorist said, that he was more interested in keeping his principal than any interest he might earn.
That makes sense when one considers that one can loose in an investment far faster than one can make the money for the investment.
The important thing is to ignore the idea that money loses value because if one doesn't save and accumulate principal, that is a wad of the stuff, one has nothing anyway.
So is it better to have a wad that may or may not decrease in value, or to have nothing to begin with and be proverty stricken in one's old age.
It is important to realize that investments are not actually money.
If you own, for example, 100 shares of Dominion Resources, you are the part-owner of a bunch of utility poles, wires, generating plants, and trucks. This stuff is not going to lose value, although its market price may fluctuate.