What is the solution to today's massive disparity between the rich and poor?

Raise the top marginal tax rate to 90%. There is no other way.

So no matter how much the rich lobby for low taxes for themselves, our elected officials should not succumb to them, and the electorate should not vote someone in who does not raise the tax rate to 90%.

The people have the power, but come the next election who are you going to vote for? If there is no candidate that promises a 90% top marginal tax rate then you should think of running yourself, because I would vote for you, and I am sure millions of others would too.

If people don't rise up in this exact way they have nobody to blame but themselves. They are cowards.