Why don't creationists teach a literal firmament anymore?

People don't seem to believe in the firmament as a literal barrier of water up in the sky that collapsed at Noah's flood. I want to say they don't believe in the firmament *anymore*, but I am doubtful most creationists did. Why? Is it because it is too fantastical? The problem is that such a notion seems to correlate with Genesis and seems to make a lot of other considerations more swallowable, such as the feasibility of centuries old lifespan, adequate conditions to sustain large animal life (dinosaurs, etc), and adequate water for a sudden flood. The only "scientific" model I've heard, coming from Dr Carl Baugh, asserts that waters from the deep under the earth came up and cracked open the firmament; his model is the only creation model that solves so many fundamental problems for creationism I am literally, truly perplexed as to how his model has been seemingly abandoned by the creationist community. I know of no direct arguments against this sort of firmament, except only alternative interpretations of its mention in Genesis. What am I missing? -- It is the "canopy theory", I believe, that I had in mind in posting the question. My own only exposure to this was from a presentation by Dr Carl Baugh and by reading his old book, Panorama of Creation. I have had difficulty finding *anyone* endorsing his model, and his model is the only one that answers several questions. My frustration comes out of watching modern depictions via illustrations, 3D graphics, and simulated film artwork, attempting to use fine detail to tell what Genesis earth was like but not filling in these gaps. Blue skies, clouds, rainbows, all post-Noah, all completely against Baugh's model. Does it matter? In an age when modern illustrations like Hollywood are referenced in dialogue with apologetics and truth seekers, yes, I believe so.