It's hard to put in an equal amount of training into each aspect, especially considering the amount of years and hard training it takes to be an A level competitor in both aspects of the game, so I believe you always have fighters who fall into the striker or the grappler category.
We may see a shift in this trend, however, with modern martial arts schools training both disciplines from the start with new people. So if martial artist A trains at a gym that does equal stand up with grappling you may see a trend of fighters that actually are equally balanced in skill. I still feel people will gravitate to one or the other with one being their strong point, but that's just my opinion.
"The hero and the coward both feel the same thing, but the hero projects his fear onto his opponent while the coward runs. 'Fear'. It's the same thing, but it's what you do with it that matters". -Cus D'Amato