You're saying the truth in football the reflexes and speed matter a lot but a player also need skills to perform good in ground because without skills the speed and reflexes won't help at all. A boxer or a MMA fighter has speed plus reflexes but they aren't skilled in the game of football and if you bring them on ground they won't be able to perform at all. A skilled footballer with speed and reflexes would do much better than a young one with just speed and reflexes. Ronaldo is old in age but he still performs better than the ones who are still in their 20's.