Both MMORPG and FPS games take skill, and the only way to get that is to play a lot. You don't start out being really good.
Even if you're good in certain aspects, there's always something unique in the game the veterans have mastered that you don't know.
Anyone can get good at any game. My friend Matt for example, whenever he starts a game he's always to worst of the worst (No exceptions). However in Ragnarok and Gunbound, we got Matt to be extremely good. So good in fact, in Ragnarok using a tank build, with full tank equip (Essentially, he did very little damage), he could take out entire guilds of people higher level and better geared than him on his own
Both take skill, it's just a different kind. You need more than just patience in an MMORPG. You need more than fast reactions in a first person shooter. Hell, I've got dirt slow reactions and I'm still one of the better players (Top 10%) in almost every MMOFPS I've played.