I’m not certain “being filthy rich” is a good merit.

It means they are a net addition to our economy instead of a drain. They spend their money here, which creates jobs, and they don't go on welfare. They pay high taxes.

Doesn’t making it easy for the filthy rich to immigrate encourage the rootless international elite we see today

No because we are talking about immigration, and no "rootless international elite" is going to sign up for high American taxes when they play the "citizen of the world" game.