Apparently most enterprise users agree with me. The sales figures speak for themselves.
My experience, which granted was a lot of years ago but I see no reason it wouldn't still be valid, for large scale/volume "enterprise" purchases are that whatever supplier a given company is tied to, and whatever that supplier happens to be/can offering/supply in the price range/volume that has been given to the IT procurement people, is what will dictate what they end up with. When looking at choices, a relatively short amount of time was given to brand of CPU relative to form factor, cost, warranty, delivery, accessories, schedule, maintenance costs, rebates, incentives, kickbacks, etc, etc, etc. This procedure gets modified somewhat when it's special use systems obviously(serious CAD or whatever that needs specific graphics for example), but for a business or department or school wide roll-out of PC's for general users, as long as it was pretty current tech the CPU was a fairly small part of the equation. Mostly they pay too much for too little. Consequently I don't put too much stock in what "enterprise" use/sales are.
Maybe things have changed in the intervening years, but the last 18 wheeler load of Dells I was involved in buying for a school it was still the same old song and dance. Intel is (almost) always a safe bet, it's still an uphill battle for AMD and they can't do it own there own. I haven't seen that they really care to.