It's hard to say from what you have said. Just going from 4000+ games and you're still in silver definitely says something about yourself (Not trying to be mean). All I can say is you are really going to have to criticize yourself throughout the game, figure out where your mistakes are, acknowledge them and think about what you could do better in the situation or even a way to avoid putting yourself into a bad position in the first place. Even if the game isn't entirely your fault for losing, figure out what you could have done to change the flow of the game (More wards? Wards in key locations? Did you stay to get 5 CS over collapsing to help your jungler against enemy invade at his red? Did you never follow your enemy mid laner, did he roam freely? Could a consist ward preventing him from getting that double at bot or sneaking past blue to tower dive your top laner).
The brackets are just examples of things to think about, you'd be amazed at how effective keeping wards up in key locations can be and it will carry you and your team as your team also uses that vision that can help your jungler pull off a gank on the enemy jungler or most importantly prevent any ganks from happening. If you aren't planning on following laning enemy you better have wards so you know if he's actually going assist another lane, otherwise you're giving him free roam which only adds pressure to all lanes (Mostly bot lane).
If you aren't already, make it a habit to ALWAYS buy wards when you return to base (If you got the gold leftover). As well, get the sweeper so you can remove wards around dragon and mid lane, having constant vision of the river and your jungle entrances will ease ALOT of pressure on your entire team, removal of enemy vision (The sweeper) will only add pressure to the enemy team. Try to make sure you always keep a pink ward active, maybe not in a big traffic area but watching over a key entrance/buff in your jungle that the enemy jungler is unlikely to go into but will pass by. I've had pink wards that have been placed that have stayed up for 20-25 minutes and I can't tell you how useful that constant vision is.
Just thoughts that came to my mind...... Vision has such a huge effect on how the game plays out.