I misunderstood then, I thought your article was regarding advising clients, not from the perspective of a retail investor. Regardless, I think retail investors do care about efficiency, they just aren't aware of the opportunity. I've yet to explain to a client the benefit of maximizing return for a given level of risk and have them say that's not appealing to them.
What people care about differs from person to person. Your example of investing in an absolute oriented Asian equities manager reflects that you are much more concerned about losing money than you are about the level of return. Someone who buys a levered equity ETF cares more about return. MPT doesn't require checking a portfolio with any level of frequency. It's just a process that provides guidance in decision making.
If our clients could embrace that when investing for the long term, volatility isn't as relevant, we would all be better off. But again, as you alluded to, all investors have to deal with behavioral tendencies, which means volatility is always relevant.