As a fairly regular user of the Edinburgh-Manchester service I'm cautiously optimistic about the current inadequate, noisy, uncomfortable DMU's being replaced eventually by (slightly) more commodious EMU's and to the route not having a Bolton-Manchester local service tacked onto the end of the journey.
But here's another idea. Keep the aforementioned DMU's, and delay things still further by running these 100mph units up a rural freight line which doesn't even allow a 150 to run at top speed. Richard Branson will love this. He'll have to strengthen all his trains because everyone who actually wants to go anywhere will be taking them from Edinburgh to Preston on the way to Manchester, rather than trundle across vast tracts of uninhabited moorland at roughly the same speed as the Midland Railway managed at the turn of the 20th Century.
Yes the S and C was a mainline, but only because at the time, everybody had to have one. Hence the equally uneconomic and scarily profiled Waverley route which it moved on to after Carlisle. It's a staggeringly beautiful line with a real role to play in linking isolated communities, giving access to the countryside, and diverting freight off the WCML. It's not an option for through Intercity services.
And having travelled a few times on both the above routes in the 70's in flyblown Mk1 Open saloons with jammed windows, no heating (except in summer) and lit by wonky 10w lightbulbs, behind some toiling, claggy Class 27, I can confidently say that that was not the Golden Age!