I have experienced similar situations as you. Silver IV to bronze III typically does not mean much of a difference in mechanics, skills, objective taking etc at all. Usually the guys good enough to solo carry bronze/low silver games will go to at least gold.
Early silver is quite toxic because its a bunch of guys who may have just escaped or climbed out of bronze and think they are all of a sudden their own superstar, their ego takes over, and they tilt, etc.
The second elo I have experienced high levels of toxicity, stupidity is plat. Besides CS and some better lane mechanics, you will witness early plat as almost the exact situation as silver.