I think 1-pointer nailed this one.
There will be no significant changes until the WHBA is somehow changed to allow for management (probably lethal management) to happen.
Arguing that cows replacing feral horse is a public perception problem is a joke. As has been stated by both Bigfin and 1-pointer, there is a regulatory process in place to deal with livestock grazing. That includes public involvement.
This issue, like most others related to resource management, has to be supported via science...and the science is pretty clear that grazing can be done correctly without impairment to the productivity of the land. It can be done in a way that supports both livestock and wildlife.
I could give a FF about the publics perception, when that perception is based on emotion, hear-say, biased opinions, and anecdotal "evidence".
What matters is the regulatory process, the laws, statutes, and science.
Our job is to educate the public about all of it then apply the science via the regulatory process to manage in the best way.
You have to start by having the legal authority to deal with feral horses...guys like RobG can argue later about the cow pies on public lands.
"...the world outside, which my brother and I soon discovered, was full of bastards, the number increasing rapidly the farther one gets from Missoula, Montana." -Norman Maclean
"They were still so young they hadn't learned to count the odds and to sense they might owe the universe a tragedy"