Commuters being the only people who count is hardly GWR specific. Look at any TOC in the country. Or most other non-freight transport (including, sadly, quite a lot of cycle campaigning).
This is recent tho. If you look at the number 1 cycle campaign group for the UK, Sustrans, for decades they seemed to be more about somewhere nice to cycle on a Sunday afternoon, than a viable way of getting from a to b.
Sure it's nice to be able to use decent cycle infrastructure for the Sunday afternoon ride home from the pub lunch. But the reality is, for most people, their most important journey is the one they take too/from work, on Monday through Friday. Infact for many people it's the primary reason they have their car. Replace that journey with a cycle journey, and you take a lot of traffic off the road.
Even if people primarily use a train to get to/from work, they will often drive too the station at one end.
Yes travel is commuter centric, but that's because it's the main source of transport.
Sure, but of the shorter journeys that are eminently cycleable, a greater proportion are non-radial. Think children travelling to/from school (with or without parents), shopping, medical appointments and such. They're also the journeys that are less well-served by public transport, which is usually radial to cope with the commuter traffic, and a greater proportion of people with protected characteristics (women, the elderly, disabled people).
Segregated cycle 'superhighways' in and out of the city centre of course, but we also need to facilitate cycling for more local journeys (including to radial public transport for people who don't want to cycle all the way into the city centre). That can sometimes be as simple as providing somewhere sensible to lock your bike, or a safe crossing of a busy road. A lot of it's going to be things like filtered permeability in residential areas, and wankpanzer-exclusion-zones around schools.
You could greatly improve the roads for everyone by eliminating the 'school run' drivers.
(I'd dispute that Sustrans were the number 1 cycle campaign group, though they might be the most visible. That's probably
We are Cycling UK, for all their faults. Unless you count Cyclenation, or even LCC on its own (I think most of the effective campaigning has been at a local level).)