Is the 'unreasonable minority' you mention those who travel to/form KX to place like Newcastle and Edinburgh? Im pretty sure the long distance passengers are the Majority outside of the peaks of Peterborough and Stevenage and they are the ones that this system works for by getting them a seat for a much longer journey
You imply all Newcastle/Edinburgh passengers want compulsory reservations. I am sure they, as with all passengers, would quite like a guaranteed seat.
But I don't think many of them would be in favour of compulsory reservations if they were told they face being unable to travel at busy times of year (post #235 refers), and that it would still be a free for all during disruption.
As for the minority that would still think compulsory reservations are a good idea, I am sure they would be outnumbered by the number of inconvenienced passengers making local journeys that are only served by IC services.
For all those complaining that the railway isn't an airline, for very long journeys it effectively is, and I'd love to know the percentage of Anglo-Scottish journeys done on Advance tickets. I suspect it's very high. Personally I never use anything else.
And that's fine and dandy if you're talking about non-stop trains like the Flying Scotsman. But as it happens, LNER services are the only option for many local journeys.
Therefore it is unreasonable to make them reservation compulsory without introducing a decent alternative for local journeys - be that additional services or unreserved coaches - in which case, why bother at all?