I can only talk from first hand experience of course but getting anything white listed/installed at C&G had a lead time of about 8 months!

With banks there is a reticence to install anything due to security concerns and with some large businesses the reluctance is born from the charges incurred from working with third party IT suppliers who charge £x per kit for even the most basic update.

To be fair, this is more to do with local installs than servers though so may not be relevant. that said there are definitely barriers for even the most basic of undertakings.