One thing in Quorum and Cobalts favour is they are in highly populated commuter belts where existing services operate.
Buses were always going to pass so extending in and taking advantage of commuter market will always happen. Most workplaces incentivise travel by Public transport and with Arrivas travel club and whatever the GNE equivalent is there's obvious benefits.
And not forgetting Cobalt is scarily big and Quorum isnt much smaller than Doxford.
I'd guess the proximity to Newcsstle as a major city and associated ports and airports as opposed to a Boldon or a Sunderland helps.
RE: Go North East: Service Suggestions v2
Wistfully stuck in the 90s