From the article


An interesting argument and position.  GWR has had an almost complete monopoly on South Wales to Bristol (and London) traffic got many years, and the monopoly was made complete when the daily Cross Country service was withdrawn.   

It has been natural to defend that monopoly, and I recall a side conversation with a senior DfT^» (Department for Transport - about) person who involved who indicated there were no plans - but that's a few years back - to change that.  Not an unexpected co-incidence of the DfT with GWR when you consider the same approach taken with the Bristol - West Wiltshire - Salisbury - London Waterloo service.   In both that case, and in a the case of a Bristol to West Wales service, there was and is a demand for a service that doesn't require people to change - at Cardiff, or at Salisbury.

And - yes - it perhaps affects revenue on the core (GWR) services.   But then a monopoly can provide a service that's less than ideal for the passengers, can't it?   If I want to go from Bristol to Carmarthen I have no choice but to changes at Cardiff at present (and maybe at Swansea too).  And I can understand GWR working still with the DfT, still looking to maximise revenue on a monopolistic service without having to complete with a Welsh service which for some sectors of the market would be very welcome.

Interesting to note from https://firstgreatwestern.info/BRI.html?limit=1500&sortby=0 some ticket sales counts
Bristol to Carmarthen - 8,000
Bristol to Swansea - 42,000
Bristol to Neath - 10,000
Bristol to Llanelli - 3,400
Filton Abbey Wood to Swansea - 1,250
All are there and back figures - so 8,000 is 4,000 eastbound and 4,000 westbound

Once GWR^▸ (Great Western Railway) is nationalised, will the dispute over revenue be resolved between the Welsh government and English (British) government be resolved. I don't think so.

Sounds about right as to what happens.  But the theory is a crude one to be always applied.

First thought - open access license applications are supposed not to be primarily abstractive.  In other words to develop new markets.   And those new markets in many cases can help the older markets too.  Not Open Access, but the re-instated services from Oxford to Swindon and the west will abstract traffic from Oxford to Didcot locals and from trains heading west that call at Didcot.   But then many more people should make the journey from Oxford to Swindon and beyond, attracted by the new service - perhaps to the extent that many more people that before (rather than less) will do the "Didcot Dance" rather that waiting for the direct train which this year is only every 120 minutes.

I haven't data to say which way that balance goes in the case of Bristol to west of Cardiff, nor on the Oxford to Swindon example ... but I can tell you with some certainty that an extra service (whoever and however it's run) combed in with an every-2-hours Swindon to Westbury service run by GWR^▸ (Great Western Railway) or GBR^▸ (Great British Railways) would (under the right conditions) increase the passenger numbers on the GWR/GBR service.     That may sound perverse, but analysis suggests that annual passenger journeys at Melksham (for example) would rise from around 70,000 to around 300,000 - in other words, twice the number of trains and each would be twice as busy..  I do need to qualify that; the service would truely need to be hourly (not two trains following each other closely then a long gap for the rest of the two hours), and the ticket system would need to be such that passengers could routinely get on the next train no matter who was running it (integrated fares).

Given that GWR^▸ (Great Western Railway) will be back in public ownership later this year, it seems odd that they protested, other than under the instruction of someone senior at the DfT^» (Department for Transport - about) or GBR^▸ (Great British Railways) who didn't want to be seen directly interfering. So perhaps there's some kind of English/Welsh railway turf war going on?

Of course the Welsh could have sweetened the deal/mixed up things by offering to rebuild and return services to Pilning station and contribute to electrification of the Filton Bank. Hard to object to that.

For their part, GWR could quietly whisper in the ears of AM's how direct trains will make it more convenient for those in West Wales to fly from Bristol instead of Cardiff. That might provoke a few reactions.

It is reported in the Bristol Post


and in the Swansea Bay News on the Lumo proposals:


Could it be that First's team at GWR also see an issue with more though services to England from west of Cardiff reducing income for First's team at Lumo ... on beyond 2026 ...

Oh yes, I'd forgotten about that one. The tangled we we weave eh?