What Is The Cost Of Amplifier Casework?

I don't think the styling of the chassis has anything at all to do with the quality of the stuff inside. Plenty of great amps are packaged up in plain, well built, simple chassis. I think a chassis should be well built, but pimping the thing out with metal accents, ornate dials, big fancy fasteners, and gleaming finishes is just eye candy that has absolutely nothing to do with the function of the thing. I don't think it says anything at all about the quality of the sound. 

I say styling exudes quality...surely it must be wonderful if it looks that way.   I strongly suspect lots of people buy the styling even before listening to the black box.

It exudes quality... In the machine shop they contracted to fabricate it. I'm sure people buy stuff based on how it looks. McIntosh doesn't stick those giant dials on everything because they tell you vital information. They look cool. Most people don't understand what's inside the box or what it's doing so manufacturer's try to communicate something about it through the box itself. The form has almost nothing to do with function though. Speaker cabs at least do something functional according to their form. 

I suspect that much of this industry's marketing target is towards: "pride of ownership". Fancy case work would be an obvious choice to those ends. 

What are the chances of a manufacturer getting the internal amp design to sound right if they can’t get casework that is functional and looks good?

Why does having the case look good, reflect on how it sounds.

It’s what’s inside that counts. Many times it’s prototypes that sound better than the production versions. This is why Schiit are making a big impact on the hiend, great internals average budget exterior.
This way you can have hiend sound without the exorbitant costs of "glitzy" casework that does nothing for the sound.

But then there are "pseudo" audiophiles that buy the most expensive "glitzy’est" looking equipment/racking, just to show it off for it’s looks, but have no idea if it sounds good or not, as they have no ear.
These are usually the ones that stack their "glamour" pieces in-between the speakers so they can ogle it and the led lights while listening, but they have no idea that the "stereo image is being greatly compromised" with all that racking and equipment and sometimes a tv as well, in-between the speakers.   

Cheers George