The main reason radar guided missiles are used more often than optical is simply because the main long range sensor on most aircraft is a radar. Stealth technology will change this so other sensors and missile tyoes might proliferate. (I have heard that Vympel are developing a fuel sniffer missile that will hunt down aircraft by their engine exhausts. (Don’t laugh… during WWII diesel smoke sniffers were used to find U boats and other naval vessels).

During WW2 German single-seat night fighters knew they were on the right track when they smelled the exhaust of Lancasters. And in dogfights they said you could smell the guy in front of you…