Interesting analysis. But I have a few points worthy to bring up.

In Canada, our financial industry is more regulated than the USA (we didn’t suffer the same recession in 2008). So that is one hole in the hypothesis that tight regulations are a reason for inequality.

In Canada, many high-ranking bureaucrats are now making CEO-type wages. I think they too should be considered part of the inequality.

As Bob Wyman pointed out, lowering the top marginal tax rates puts pressure on the high-income earner to ask for more money. So the top get a raise, while the rest don’t have as much bargaining power.

And we should put in the people who are able to hide their income with shell companies and offshore accounts. They do affect the inequality, but it may be hard to determine by how much.