This is perhaps down to the philosophy of how you run a railway, though. It could be argued that you terminate two of those four at Newcastle and have through passengers transfer onto the other two, making the non-VTEC one longer (the VTEC one presumably is already at maximum length - but even that presumably would have additional space north of Newcastle as a lot of its passengers would be travelling London to Newcastle). This would free up paths for a stopping service serving new stations.
Disclaimer - I am not a local, but this is a philosophy that could apply elsewhere on the network; it could be argued that slightly fewer but longer inter-city services (the same or more number of seats with slightly less services, you could for example have two 10-coach trains replace three 5-coach), making people change for some of the less-popular through journeys, could, in some areas, benefit the railway by reducing congestion and giving scope for less profitable but more socially-needed services. Local services on inter-city routes are notably absent throughout the country away from the major urban areas, and have been since Beeching. Not sure that would happen in the current climate though - and I'm not proposing reducing the frequency of services on busy corridors like Reading Birmingham for instance.