There aren't more speakers of Comanche because the U.S. government has made a practice out of destroying culture, language of indigenous peoples. Less than 1% of Comanches can speak Comanche.
I was fortunate to have a great grandmother and grandmother to teach me....although, they were against...
I agree, as a speaker of the Nʉmʉnʉʉ language it is very difficult to learn...mainly from the fact there are so few speakers fluent in Comanche to have conversations with in everyday situations.