You asked how crates prevent these behaviours - from my previous post...
every time he finds something and gains pleasure from chewing it, that behaviour is reinforced in his mind - you need to prevent it happening in the first place so that the behaviour does not become ingrained
When you are supervising the pup during the day and you find him chewing something it shouldn't, you can say 'leave it' or similar, and give him something that belongs to him as an alternative. Dogs are very aware of their resources and will quickly learn that something of 'his' is ok to chew, something that isn't his is not ok. That said, all toys etc actually belong to you, you just allow him to play with them, but I'm sure you get my drift.
The point is, at night, you can't supervise this, so a crate is necessary to prevent bad habits forming.
Furthermore, as dogs don't want to foul their own nest, crates train dog's bladders to go longer between wees as they will hold it until let out (according to our vet, this is a physiological thing, as well as psychological).
You can't keep everything out of reach, my dog was fond of chewing skirting boards, bookcases, edges of carpet etc. It was only by literally either having him in the crate, or never letting him out of my sight for about 8 months that he learnt.
Why do you have such an issue with crates? I take your point that they are a recent preference of behaviourists, but then again, it is only in the last 20 years or so that the training of dogs was expected...