A clustered index is certainly not actually the physical order of the data stored on the disk, at best it tends to approximate it by placing data associated with similar keys in similar blocks. You would have to actually physically reorganize your entire clustered table or index to get it in physical order, and often you lose performance by doing so.
The performance impact of randomly distributed keys on any ordered index on that key is certainly real though, so I agree with you there.
The performance impact of randomly distributed keys on any ordered index on that key is certainly real though, so I agree with you there.