The dictionary definition of skill:
noun
1.
the ability, coming from one's knowledge, practice, aptitude, etc., to do something well:
Carpentry was one of his many skills.
Dexterity, reactions and quick thinking have nothing to do with it. Planing and working out a strategy is as much skill as being able to execute complex inputs in a fighting game.
That's not the same definition I'm finding.
In general, skill is meant to mean anything involving dexterity, or a talent that is built up (e.g. learning to draw or write).
Even thinking colloquially, do you ever hear people say "yo, you got mad skills for winning that last turn in that chess game"? No, you don't, because chess is not a game of skill, it's a game of strategy. Anyone can play chess, they just have to understand the rules and strategise based on those rules. It's the same with turn based RPGs. They are the easiest games to play - you just click through menus and walk around the overworld with basic movement - but they often have a lot of rules you have to read up on and you strategise around those rules.
Skills are recognised as such because they aren't something anyone is capable of. Not everyone can run real fast, not everyone can lift something super heavy, not everyone can input flashy combos in fighting games. This is because we all have different bodies, so we can't all be capable of the same physical feats, no matter how much we practice. A crippled man can't walk no matter how hard he tries. Similarly, you could understand all of the best art techniques and know what you need to make the most beautiful art piece, but that doesn't make you an artist - steady hands do.
Planning and working out a strategy is not a skill, because it only requires one thing, and we all have it - a brain. You may need a skill to CARRY OUT strategies, but not to formulate them, and formulating strategies is not a skill itself since anyone can do it. And your proficiency in formulating a strategy is only defined by the knowledge you have of the presented problem, which is again, something anyone can acquire theoretically (i.e. everyone has the power to attain new knowledge, it's just a matter of whether or not it's available to you, and how developed your brain is might effect how long it takes for you to understand it).
Back to the initial point though, there is no need to try and big turn based RPGs up as "requiring skill", because by dictionary definition, they don't. It's not a bad thing either that they don't - they are like chess in that they are games that are about thinking, and that's fine.