Of course training is valuable, and better quality training gets better improvements, no elite level of sport is reached by just having an innate ability, but the difference between the very best, and the rest is vast, not 1%, which your statement, "99% of skill" suggests should be the only difference between the average and the great, as long as they both have access to good training and put the effort in.
I wonder why City want to spend money on Cucurella, when they could just train anyone to play at least 99% like him?
Absolutely - but that still doesn't explain how some of the best players in the game, like Greaves, Best and Worthington thrived at the top by doing all the wrong things. and frequently dodging the right things when they could!