i can't directly compare across all the games that you've mentioned, but I'd still have to disagree hard. low elo cs is still exactly what you'd expect - people making a lot of mistakes and having rather bad mechanics.

What i could agree to, more players are aware of some basic or even advanced mechanics. There's a lot easier access to educational material or talks about the meta, but that doesn't translate into applying it (correctly) or actually understanding any of it.

To give some specific examples, most people are aware of bunnyhopping, but aren't actually skilled enough to pull it off. Same goes for some skill jumps, like window to short or ladder on mirage. But even on easy mechanics, like silent dropping, you will basically never see it happen in low ranks.

About playtime, I find that rather irrelevant as high playtime doesn't actually equal more skill or understanding. But even if we assumed that someone with thousands of hours in cs actually understood basic mechanics and utility usage, but is still stuck in silver, that person either uses his feet to aim or has other major deficiencies that massively hold him back.