It's two fold.
1) It isn't less competition from other waterfowl on the nesting grounds, they are simply outcompeting other nesters. Snows and cackling geese are one of the primary reasons brant numbers are down in the Atlantic flyway. They are outcompeting the brant for nesting habitat. I doubt there are less predators on the nesting grounds, personally I think lean towards there being as many, if not more. But when you have so many birds surviving to reproduce, I doubt predators really end up putting a dent in these populations.
2) Where the majority of snows winter, primarily in the central U.S., there is a TON of winter crop for them to feed on which is increasing winter survival of both adults and juveniles. This does hold true for the Atlantic flyway as well.
What I think really needs to happen is a focus on adult birds actually, not juveniles. Juveniles their first couple breeding seasons tend to have less success compared to adults, as they get shunted from better habitat, are inexperienced, etc. Kill a juvenile who may produce no goslings..2..5..etc versus an adult that produces 7..9..12. Have predominate population of juveniles attempting to breed versus seasoned adults..I think that would do a lot of good..A ton of juveniles already get harvested from August-May in the grand scheme getting hunted from Canada down to Texas and back up to Canada in the spring.
I highly highly doubt we will anytime see a "population crash" of snow geese given their sheer abundance right now, farming practices that are only liable to expand over time, and their consistent good hatches up north. Bgibson, if you know your population ecology, you would know a population such as snow geese are not growing and cannot grow exponentially. This would imply they have unlimited resources (which I can assure you they are food and habitat-limited) and a host of other assumptions very few populations actually meet under ecological conditions to grow exponentially.
I really don't see any major undertakings coming soon to take on the snow overpopulation. It would multiple seasons of people on the ground addling or oiling eggs to see results, not an overnight fix and not a cheap one. However, with the snow boom, it has become fairly popular to do after other seasons go out. I've seen a ton more guys out chasing snows each year in NJ and in AR, the states I primarily hunt. Gotta factor in economic pros/cons associated to snow goose hunting, cropland damage to farmers, etc too. Take away a ton of birds to hunt, what implications does that have for snow goose hunting economy (guides, license sales, decoys, leased land, shotguns, shells, etc)? Not an easy compromise to come to..
I would personally love to see the feds allow us to use e-callers during the regular season as long as we are only hunting over snow goose spreads.
Just my two cents..