I wouldn't take that too literally, firstly those are Gruber's words and secondly, there isn't anything stopping you putting the Mac Pro on the floor so long as the cables reach.
Apple themselves admitted as much. They focused too much on making something beautiful and small. Neither of those things matter to a pro, especially for a desktop.
And not only that, even Apple with its vast resources cannot keep the machine up to date because the components are so tied to the case design.
A nicely designed item is unrelated to where it should be placed. The OP was specifically saying that Apple lost the Pro market because the unit "demanded" to be put on the desk which is absurd since the Mac Pro can be placed anywhere that the cables allow it to.
I think the OP's point is that the Mac Pro is not a nicely designed item. Design is all about tradeoffs. In this case, Apple had to decide whether to prioritize form factor and appearance or upgradability and performance. They chose the former, which turned out to be the wrong design for the target market.
The feature that allows a current Mac Pro to be placed on a desk comes at the price of more important features like being able to easily upgrade and expand a Mac Pro. Could be wrong but I feel that's one thing that OP wanted to express.
The trade offs made give it a small footprint, I've seen many cheese graters on desks and they were fine. Initially I assumed OP meant the same thing as you highlight but after talking about keeping a pros desk clear I assumed they were being more literal. If the issue is that Apple made a small computer that compromised on its core requirements then that's fine but to say that the issues stems from making a computer to sit on a desk alone is absurd.
Couldn't agree more, I mean hell I put my G5 (cheese grater) behind my monitor (on my desk) back in the day _just_ so I could more easily dust my machine. Pretty? No way. Ergonomic? Yes.
my issue with the current Mac Pro is that, yeah cute packaging, but I need a second tower/accessory/etc when I only needed one before so I immediate get new clutter and cables all because someone had a "cute" design for the main computer
It's not important where I can put it - the act of designing something that should be placed on a desk prevents them from designing what I want. A Ferrari is a desirable sports car and a terrible cargo van.
You're refusing to accept the simple reality that professionals couldn't figure out how to put a computer on the floor. And that's how Apple lost an entire market!