I think the author is a bit too narrow in their definition of "political clout". They seem to define it as the ability to personally influence federal policy. However, as a class, people with $4M in wealth or more have an immense amount of political clout. Most contemporary US local, state, and even federal policies are geared toward attracting and retaining these people. Think property tax caps, mortgage interest deductions, zoning, traffic and transit policy...etc.
If you have $4M in wealth, you might not be able to personally call up a lawmaker and get them to pass your pet law, but governments everywhere are bending over backward for you and people like you.
If you have $4M in wealth, you might not be able to personally call up a lawmaker and get them to pass your pet law, but governments everywhere are bending over backward for you and people like you.