Randomness and ELO do not mix. ELO is supposed to be about measuring skill.
It's not about luck and skill as much. It's about the probability that the better player will win. Since ELO works fine in Chess even when you exclude the very best and the very worst players, it will work fine in Elements.
This makes no sense, you contradict yourself. Chess is about skill and match-ups are random. Elements is about luck, drawing cards after RNG shuffles your deck, and match-ups are not random. Chess leagues that use ELO run for years so your ELO equalizes at your appropriate skill level. Elements league ran for 2 months, now 3 months, which is clearly not enough time to equalize the skill of players, if ELO were even capable of measuring skill on a game built around random drawing of cards.
Picking a deck that MIGHT counter your opponents deck, based on what you know of that person and what decks they generally use, still will not guarantee a win because of RNG.
Random match-ups in chess usually pit you against someone with an ELO around your own, and that is because there is no point in playing against someone that has an ELO 500 more than you which proves they are more skillful at the game. But here in elements, if the lowest ranked played the highest, there is still a really good chance the lower ranked person could win.
So if one person gets really lucky at the start of the league and get their ELO up real high, and slows down on playing, someone with a low ELO rating will be required to play a lot of games to try and catch up, and it is possible to catch up because it is not skill based. In chess your ELO won't fluctuate all that much once you have played a good amount of games to equalize it out, unless you can get really good really fast, which usually will never happen. But again, in elements, a player can go on a winning streak with a low elo against all the top ranked people, and their ranking will go up, and that is because of a luck based game. But it still requires too many games to try and catch the people at the top, all the while risking your points because you MUST play to gain more, and they don't have to play at all to remain at the top.
There is no incentive to play when on top, there is tons of incentive not to play though. And just because a few people do continue to play while on top does not mean anything about the whole league community. It already has happened that someone on top stopped playing and was still rewarded from lack of participation once on top.
I also agree with everything ralouf said when he compared elements to mtg. The ability to block attacks and play cards to counter your opponents cards while they are playing shows how much skill is needed in mtg over elements.