I haven’t been part of that conversation but my .02.
It seems clear to me that if precipitation in a storm of yore fell at 32.0° and precipitation in a storm today fell at 32.0° both (assuming the column above isn’t torched) would be snow.
But obviously that’s not really the question. If it’s snowing at 32 it’s a marginal track to begin with. It’s unequivocally warmer, and high latitude warming probably has an effect on the overall setup, i.e. the amount of blocking, cold source aloft and at the surface, making it more likely than not that a similar surface low track produces a different outcome for a variety of reasons. Not always of course, but we probably see more marginal misses today than we did in the past which had marginal misses as well of course.
I am in no way saying that it’ll never snow again in a marginal situation, but it’s an interesting question to ask.