Saying you literally play every game with a 4 man is exaggerating to say the least.
Is there a significant amount of 4 man + 1 games? Yes.
Are all or most of these games negative experiences? No
Are all or most of these teams trolling/toxic towards you? No
Are there teams which you simply cannot carry if they fail? Absolutely
Are there teams which they simply cannot carry you if you fail? Absolutely
Bottom line it is easier for most people to blame the system rather than their own ability to create their own positive game experience. If you want to enjoy league more, stop blaming RIOT and Dynamic que (even if it sucks), and start focusing on what you can do personally in each game to improve the outcome.
Study your games, Study your mistakes, Make yourself the best you can be, don't rage/afk/ or be toxic, treat others with the respect (even if they don't deserve it), focus on winning and helping your team. I promise you your game experience (and winrate) will improve.