If it becomes a mega-brewery thing, it will filter down all the way - and likely 'we' will have very little say in it.
If mega-breweries change their process and can make the same beer, more cheaply with unmalted grains, I can't imagine that the malting-companies will survive on just the micro/home brewery market.
As a consequence they will close or be hugely consolidated, the range of available malted-grains will decrease and 'we' will be forced to change practices as well.
its already a mega brewery thing - its just not all that common in this particular part of the world. Go to africa, where resources are scarcer and barley at feed grade (pefectly acceptable if you are brewing with enzymes) is a lot more available than malt, and sorghum and millet is much more available than that, and you'll find plenty of breweries using high percentages and even 100% unmalted grains.
It is one of "the" debates in the brewing and related industries at the moment - barley and enzymes is cheaper, less energy and water intensive and less demanding on supply chain than is malt brewing, and apparently (debatably) gives product of equal quality (remember we are talking mostly anout mega lager type beers). Anyone who's brewed a gluten free beer from that sorghum extract has made a beer this way - the stuff isn't made out of malted sorghum, its made with raw sorghum and enzymes.
Your worries are IMO unfounded though - its always going to be a mega thing primarily. The range of malted grains is unlikely to diminish - to be honest, basically everything but stock Pale/Pilsner malt is
already a niche product for the craft market. That market isn't going to go away. Sure, some big maltsters who primarily supply the megas with pale malt might go down in flames, but the guys who supply most of the good smaller demand malts probably wont see a big change in their market. I think that largely, they aren't the same people. Prices might go up though and getting malting grade barley might be an issue.
