Just an idea
Seems as you have issues keeping players interested, and people love the whole silver superstars icon style of upgrade evos. Why don't you do a whole evo your own icon every season? I know it seems a bit ridiculous, but why don't you let us pick one icon out of I don't know 3 or 4 a season and let us apply our own evos to them? Don't add any sort of price to it, and don't make them as powerful as actual icon cards of course.
But It would keep people interested in playing the game and would give everyone the choice to have a unique experience of the game. You will obviously have the meta players that all go for the same stuff, but for the rest of us it would be a fun and unique experience where we can create different icons suited to our teams and style of play.
I understand that the whole idea is to get people to spend money, but if you made it so we could pick like 1 of 3 icons in a position that we could build ourselves, I feel it would help with player retention at least. Honestly, you need to bring something unique and fun to the game soon or people are going to leave in droves and there won't be a game anymore. Not with the cost of licensing and advertising involved at least.
Also, if you do adopt this idea and it works, don't say that the player base never tries to help you. I've been on fifa/fc for like 16 years at this point, and online for 13 years. I've also spent a fairly decent amount in the past (I don't anymore) towards this game, because I enjoy it and enjoy playing against people online. Obviously it is up to you and the highest heads at EA, but you need to do something fast to fix this game or make it more enjoyable, otherwise your player base is gone.