I don’t know if it’s gamed or not, but the average is a lagging indicator but definition
Most people are not willing to inform anyone who they are really voting for. They are tired of being labeled as homophobic, Islamaphobic, misogynistic, and racist. So they just keep their mouths shut and tell people what they want to hear and then do what they want when they actually vote.
That is why Hilary was going to win in a landslide that did not happen. The only people that believe the MSM polls is the MSM. It is going to be a repeat of 16 in 18, and in 20.
The thing is that averaging polls over time show a picture of where things are from date “X” to Date “Y” when the only number that counts is “Y”
On election day it does not matter how people felt three weeks ago.
Lastly, polls measure sentiment elections measure turnout.