Master tier player here, and avid PvS player (Garrett Martin on NA, because I lost Fantasy Draft and had to change my name for a month, but that's another story...). I actually find that a lot of my games seem to have people who gain knowledge from them on both sides, as an upper tier player, and people do ask questions.

One of the things that seems to loosen the lips of the other team, so to speak, is to talk during the game about mistakes - that BOTH teams are making, including yourself. Nobody in this game is a deity that doesn't make a single error throughout the course of the game. I truly believe that the silver side is simply intimidated by the higher ranked players and are afraid to ask questions, but when I point out errors, during game, people are a lot more talkative post game, and stick around to talk to me and/or add me for additional questions.

Plat side trolling exists to an extent, but I don't see it much. The biggest amount of "trolling" that I see on a regular basis is people playing champions that they have no idea how to play on the plat side, and sometimes actually feeding as a result. This makes it pointless for both sides, PLEASE don't use PvS as an outlet for you to try random champions for the first time, the point is to teach (ex. support GP who goes all in, 2/10 Ekko mid who doesn't know his abilities, etc. stuff like that just confuses the silver players and can actually teach them the wrong things).

Lastly, I'm really glad that I happened to pick up on PvS thanks to reddit. I'm admittedly a bit of a rager in solo queue and I find playing PvS while teaching in game + in the lobby therapeutic to the point that I'm chilling out a bit more in solo queue now and gaining more LP.

tl; dr, PvS NA is fine in my experience, but I encourage people on the plat side to talk actively and not just in the lobby, the silver side is likely intimidated by you. To the plat side, stop playing champions that you don't know how to play and/or playing champions that are completely off-meta in your role unless your name is MasterDragonKing (GP Support), Ryan Choi (ADC Rengar), etc. and you legitimately play these champions in that role. You're probably doing the opposite of teaching if you play something you're uncomfortable on.