The argument that popular equates to good doesn't wash. As de Rouchfoucault said, "If fifty thousand Frenchmen do a foolish thing, it is still a foolish thing." There are undoubtedly more people with velvet Elvises on their walls than reproductions of Rembrandt. The typical person is not fit to judge what is musically "good" (in terms of quality) because his sampling for comparison is laughably limited, and his basis for judgement is based on familiarity and hype.

It's like asking a little kid to tell you which are the "good-tasting" foods and which the "bad-tasting" ones--he's more apt to judge by color, mushiness and whether his mom wants him to eat them than by actual flavor; a strange food won't even touch his tongue before he spits it out. But if he sees a friend or (better yet) older sibling digging into something, it will instantly become his favorite food.

The modern music industry is about sales, not high quality; the corporations' main goal is to push "product" to the most impressionable, most spendthrifty markets. Quality and heavy promotion aren't incompatible, but the latter is in no wise proportional to the former.

Nor does "good" equate to "favored by someone", which doesn't even require that it be mediocre. We've seen plenty of no-talents on TV reality shows who thought their singing was da bomb.

Undefined in the question are "good by what measure?", "who is to decide?" and "in what context?" It's my view that we DO have people qualified to judge--those who have been exposed to a wide range of music and can actually articulate what it is about a piece of music that works or doesn't. We can't predict what will be considered good music in years to come. But neither are we musically naive. The world has already seen atonalism, quarter-tone music, computer-generated music, minimalism, fusions of all sorts, rap (music without the music), sensory overload, even John Cage's butterfly. Every musical variation has been tried in some experimental form, combined with every medium that exists. There's plenty of room for innovation yet, assimilating these facets into mainstream music, but there hasn't been a true innovation since synthesizer chips and computers made anything musically conceivable actually possible, now, by anyone. Well, except the smellophone, which still requires extra hardware.

In short, there's nothing we haven't heard. To shock the musicati, you'd have to orchestrate natural disasters (why do I think of Britney Spears?) No complete concensus is possible, due to personal tastes, and we can't predict what will be good music in the future, but today's bad music is likely to remain in the dustbin for eternity--once the tweenies tire of it. {checks watch}