Bronze, Silver, Gold, Plat, and high Diamond all the same really. Only differences is warding and vision control, and objectives. Down to mechanics is =/=
The reason Bronze is hard to get out of is well? There is too many people in bronze. It's the majority of the games population and why? Because Silver+ has less spots open to get in, especially Diamond+ where there are fewer spots, and Challenger and so on where there are hardly any.
Basically you win=you knock someone out of a open available spot and climb. The more this becomes apparent as you climb that this is happening and is the actual case. Yes lots of people can get out of Bronze if they played enough, but there is a huge luck factor and typically unless you're in a party, you will not have a huge winning percentage. You can't carry every game, you can carry most but not all.
Solution? Riot opens more spots for all Leagues so more people can get in and there isn't mixed skill levels between bronze players competing for Silver.
Personally I wished everyone was based on KDA and performance, not if you win which is stupid.