I am not well versed in other disciplines, I focus on BJJ, some boxing, and a hint of Muay Thai....aka-LE self defense. What happens if a fight goes to ground? I'm asking an honest question because I do not know how other disciplines address it. With so many HS and college wrestlers and many people emulating the MMA they see on TV/Youtube, ground fighting is a valuable skill. Most fights I see end up on the ground.
I can only speak for the karate I did when I was younger, but it was rarely addressed. The main answer was to keep them off you with your feet (either kicking at knees, upkicks, or pushing at the hips) while attempting to get back up.
I always thought the lack of ground work was odd when the founder of the style and several of the higher ups held black belts of various degrees in Judo. Very little of it carried in to what we did.