One thing is minor is unquestionably more dissonant than major; a major chord (in just intonation) is one of the most powerful sounds in existence which is why

One thing is minor is unquestionably more dissonant than major; a major chord (in just intonation) is one of the most powerful sounds in existence which is why Baroque music almost always ends on major -- ie not to "sound happy" but to end with a bang. This dissonance is related to why a composer like Bach has many, many compositions in minor (and massive ones like the B-minor mass), but not much later, you see composers using minor less and less as they moved towards more consonance (along with modulation of course). For instance, in all of Mozart's violin sonatas there's only one minor. And it's freaking awesome ... but he didn't want to write more than that. I think that while dissonance was interesting to Bach, it was less so through the rest of the common period, so that favors major. I would also add that Salsa as a genre uses minor keys for happy tunes all the time.