I have a fairly hefty, large-sized red dragonfruit plant growing along a length of chain link fence. It's just Galvanized poles and chain mesh. Not even a top bar. And this plant produces very good crops, and seems to not mind the lack of anything wooden to send epiphytic roots onto at all. The plant largely supports itself, and lengths that become slightly restricted owing to the limited size of the mesh holes don't seem affected by this either, and produce as well as those that aren't constricted. I suppose even if this did prove and issue you could probably get mesh with larger hole sizes.
I'm wondering if there's a reason we don't see this done commercially. From where I stand, farming them this way seems to make the most sense. It's relatively expensive to set up, is strong, durable, and most importantly would maximize surface area for bigger crops and light exposure. The real advantage would be to taking advantage of vertical space, which most 'umbrella' type trellises don't.
Is there something I'm missing here?
I don't see any downsides, and in my experience...there kind of doesn't seem to be any.