it’s passable, but for the best environment its both too short and too narrow. Bearded dragons are semi-arboreal and providing vertical space with climbing furniture is a great way to provide enrichment and exercise.
I think a lot of that has to do with shipping and manufacturing costs which increase quite a bit with size. Once you get above about 36x18x18'' you start getting into custom builds either special order or make your own (which is probably most cost effective). The more space you can provide the better. It allows for more options in terms of lighting/heat and terrain.
Yeah that would be pretty good. I would browse through the DIY and Enclosures section for some examples of repurposing furniture into a viv. A lot of folks have had good success doing that.
Yep! Cooper is spot on, commercial vivs start getting rediculously pricey at large sizes. Unfortunately the pet industry doesn’t really cater well to the needs of the animals it also sells :/