I see you couldn’t resist reminding everyone about commuters and what they pay for their travel!
Quite rightly too. There is widespread economic illiteracy about the realities of commuter provision, be it bus or train (or road network capacity, for that matter) and each time the reality is explained there is just a chance that someone might read it and learn.
A long-distance train on one of our main lines, especially the E and WCMLs but possibly Chiltern and GWR too, will run all day and may be pretty well filled most of the day every day. It doesn't take a lot of thought to see that it will make a lot better return on the investment in commuter capacity.
A commuter train, even though it may be full to bursting point, will only be making a couple of journeys loaded in the morning and evening peaks and probably isn't used at all over the weekend. This is exacerbated by the staffing costs where, unless you make the staff work split shifts, two crews are needed to cover the needs of people making just one relatively short journey each way in the day.
I know that in the SE lots of trains are longer and fuller through the day than used to be the case and commuting distances are getting longer, but there is still no contest in the return-on-assets competition.
p.s. I meant to illustrate it with a comparison from 40 years ago: we went to a party in S London. Our host grumbled about his season ticket costs, until a quick comparison revealed that his fare per mile was
less than the quarter fares we had just paid to get there 150 miles down the WCML!