Are you around Silver 1?
Plat 5 isn't that big of a jump from Silver 1. I'm Gold 2 and only play for season rewards. After promos I'm usually placed in Silver 1-2 and I really don't notice a major difference. Plat and Gold players just pay attention to team comp more. Subtle things like that matter. Skill wise I don't see a big difference. They can feed an Irelia same as a Silver player.
There are people who get to plat 5 after hundreds and hundreds of games. I saw one the other day who made fun of me for being Gold and said they were a better player because they were Plat. I peeped their profile and sure enough, Plat 5 after 600 some games this season.
You can get to where you're going if you have enough time. The system does reward grinding.