>Oh, we can electrify lines alright. The issue as the article says is the economic feasibility of doing so.
Well exhibit number 1: Midland mainline electrification:
There was a business case that showed that the electrification project would both be completed and pay for itself in under 10 years due in a large part to savings associated with the maintenance and operation of ageing diesel trains.
The UK government decided that this didn't provide a satisfactory return on investment and instead decided to rush ahead with HS2.
Subsequently, they decided the Midland mainline would benefit from the electrification of the London end of the line (ie. commuter services) and having to operate diesel/electric trains.
Last year Network Rail finally said they want to electrify the northern half of the line by 2050.
So whilst a few decades back we were able to electrify the West Coast Mainline in its entirety, I suggest that is no longer the case.
Likewise, with the government (and major political parties) backing HS2, the likelihood of a rail project going ahead is inversely proportional to the economic feasibility and viability.