1. Moving some platforms to the cloud, does not eliminate the requirement for internal support, from my experience, support is always required, thus it is impossible (at present) to eliminate internal technical support staff, so you might as well use them to the extent of their talents.

2. As you noted, Cloud based platforms require high bandwidth in order to operate in a manner that does not impede on general workflow, especially for media rich content, a 1Gbit connection per user (trivial on a LAN) will be very expensive on a WAN connection.

3. Last but least, as it in my mind the most crucial element. I am reminded of two events that happened at the same time frame, that in my view cultural institution should regard as a serious warning sign.

The first was the political pressure and subsequent bowing to censors by the national portrait gallery when it displayed works by David Wojnarowicz. The second was the removal of the wikileaks documents and shutting down of wikileaks services hosted by cloud providers at the behest of a certain political figure in the US. The shutdown was performed without due process of law, the data simply vanished because of political pressure.

Cultural organizations present material that many may find offensive, the pressure from political interest groups can be a source of discomfort to cloud providers and their shareholders alike. Without the assurance by the providers that service will be maintained at all times unless a cease and desist court order is presented, museums cannot afford to store the sum total of their intellectual material in a service that may choose to remove it on a whim.