It's likely a mixture of somewhat, not at all, and very reasonable people.

How many are they? It's a distribution, the more influence one has, and willing to exercise it, the more they contribute to running the show.

A few holds disproportionate amounts, but the numbers add up, granted a bit of coordination is at play.

It's often quite reasonable to try to change the world, so I think this is wrong.

Sometimes the world is even easier to change than yourself.

Even assuming it’s true, the fallacy in the quote is ignoring all the unreasonable people who try to adapt the world to themselves in ways that are harmful to everyone else. If the first sentence is true, then all destruction also depends on unreasonable people.