Northern is still an economic basket case which the Rutnum letter suggests will get a whole lot worse if Pacer replacement does go ahead. 360s, being modern, have high leasing charges. 319s are doubtless a lot cheaper.
In the lead up to an election Senior MPs finally realised that Northern is a unique franchise. FGW, EMT, Anglia and SWT have low-usage rural lines balanced out by profitable Intercity services, so it should be expected that Virgin and East Coast profits subside Northern services to create a level playing field.
I never suggested 360s going to Northern, I suggested sending them to LM for a consistent fleet if that's the only consideration for rolling stock cascades, which some people seem to think is the case. Of course 319s will be cheaper than 360s but then 319s aren't cheaper to operate than 323s and may need costly re-engineering alongside costly platform lengthening to be able to take over 323 duties.
The next Northern franchise will probably require proportionally less subsidy initially. Northern will take over the Manchester Airport to Lancashire/Cumbria services from TPE (which perform well), will provide a more useful service on the Helsby-Ellesmere Port branch (rather than a poorly timed token service which no-one uses) and will off-load the low usage Barton Humber services to EMT. I can't see that having a positive effect on EMT's subsidy though!
West Anglia pays a premium to operate.
Wait a minute are you comparing the profitable part of a franchise with a whole franchise? Or do you mean Greater Anglia and you're unaware that Greater Anglia's finances have been poorer than expected and they've been in receipt of revenue support from DfT meaning DfT actually pay 1.5p for every passenger mile on Greater Anglia.
FCC, East Coast and SWT were the only truly profitable franchises in the most recent year's figures.