Tom Ewing is wrong because he simplifies the idea of the "test of time" down to mere personal music appreciation. He seems to be saying that we are beyond judgement if we like something and it works for us.
But our musical choices reflect something about our basic nature. If I am the person who constantly says that Britney Spears is one of our best singers, and only eclipsed by Ashley Simpson, then that says something.
It says that either 1) I am stubborn as hell and willing to redefine language to fit my personal tastes or 2) that I am ignorant of experience and depth and have no familiarity with the long list of distinguished female singers.
In either case we can assume that those attitudes probably carry over to the rest of the person's life.
It's akin to someone who has lived on the same block saying, "Well this is the best place in the whole world. Bayside Queens totally kicks butt!". Or like those people who say, "Oh no, Olive Garden is THE BEST for Italian, The BEST Jerry!".
It very well might be true, but probably not, and believing such might show the limitations of your imagination, experience, or life as a whole.
And if you cannot recognize the difference in quality between Andy Palacio and Miley Cyrus, or between Ah Ha and Morrissey, then one is probably not the great visionary who will distinguish between such questions as "Do I keep my job or quit before getting a new one", "Do I max out my Roth or keep the money for entertainment, "Do I charge it or pay cash," "Do I buy that land in Arkansas from Eric Estada on the infomercial or do I build a diversified portfolio" "Do I eat the Bar-S $1.00 franks or the $7 Boars Head franks," "Do I lower interest rates to the point of no return and toss in fiscal stimulus or do I let the chips fall where they may to work out excess."
Delusional perception in music probably carry over to other parts of people's personalities, so recognizing quality and what stands the test of time is important.
I'll confess I've a fondness for a-ha, though, which I'm sure says something about my basic nature. :)