knspol You've raised some valid points and I'm sure I don't have the answers.
It will undoubtedly depend on local conditions. In my town there has been a a local hospital with empty space for as long as I can remember. There have been various attempts to sell it off, but all have failed - fortunately. There was no capital expenditure to buy property, although there does seem to have been investment in renovation.
We now have a hub/local hospital which is ideal for the new plans. One GP practice has already been moved in. The practice works in a consortium with other local practices, so they've been able to pool their resources to afford resources which wouldn't usually be available in a standard GP practice.
Empty space is now being used for a variety of outpatient clinics provided by various trusts, so patients don't have to travel to more distant hospitals. They're staffed by nurses and doctors from the hospitals. One of the wards has remained open for over 60s rehab in-beds. It isn't the same as A and E or minor injuries, which unfortunately aren't (yet) available, although the local ambulance depot is located onsite.
There are other hubs within a few miles offering different specialties. Again, they're staffed by local hospitals. The idea, I think, is to provide services closer to people's homes and in a less high-tech environment than hospitals.
There need to be enough people in an area to make it worthwhile - and to have enough patients so that clinicians aren't working in isolation. For example, it would be silly and dangerous to have a specialist cardiologist working in an isolated hub because he/she needs the experience of seeing a number of patients on a regular basis. It wouldn't really work in very isolated areas, but would work in areas where there are clusters of villages or small towns without a general hospital.