Money. The major cost of a cloud service, at least one you expect people to pay for, is the availability of resilient storage and bandwidth. Given the remit of the service is to be entirely within the EU, we couldn't use any US hosted storage service like Amazon S3, we'd have to either set up a hosting business or pay a third party hoster a ton of money.
Last system I set up that could be comparable to a small commercial cloud service (i.e tens of thousands of users with in the order of 100GB of storage quota each) cost in the order of a million pounds. That's pretty much just the cost of the hardware, not ongoing service and bandwidth costs.
Now I'm not saying you couldn't raise that as venture capital because, as you say, there's an obvious business case for it. But a cloud host isn't a 'soft' service you can set up on a dime. It needs a large lump of money spent on infrastructure and setup before it starts making money.