In Go, Why are "High Point" Openings Seldom Seen in Modern Play?
I don't have a database at my disposal so I can't provide hard numbers over time to confirm this, but I believe one of the reasons high point openings saw emerging popularity was that white was attempting to play quickly in order to overcome the lack of komi.  There was also the "threat" of playing extremely complicated joseki such as the taisha, which would provide more opportunities for black to squander his first move advantage by making a mistake in fighting.  As the "New Fuseki" movement took hold, high openings continued to see play because of experiments using more influence-oriented openings, but over time things settled down and now with the extra handful of points white is not under pressure to play so severely.  

That said, 3-5 point, etc, openings are perhaps uncommon relative to 4-4 or 4-3, but I would still not consider them rare. They are even more common if you include an approach to a corner that is ignored, and the attacker is first to continue locally - this is effectively the same things as playing a 3-5 or a 4-5 opening with a 3-4 "invasion"