There are two ways you can address this question of turnout. First, you can compare a turnout between proportional systems with what we have with non-proportional systems. What you see is that turnout tends to be higher in proportional systems. That is there. That doesn't necessarily mean that if Canada moves from a non-proportional to a proportional system, then we'll get a higher turnout. It's highly suggestive of that.
The problem with looking at it is that not many countries have gone from a non-proportional to a proportional system. The number of cases is fairly low, so it's hard to make that case. I'm comfortable saying there's probably a high likelihood that if we moved to a PR system, over time our turnout rate would increase. There are good theoretical reasons for thinking that.
You are right; people are not atoms. Voters are not atoms. We can't predict with certainty what they're going to do, but I think there are good theoretical reasons for thinking that turnout would increase if we moved to a proportional system.