This is quite literally how the system works for the majority of TOCs post Covid, for better of worse.Make it so the only way for TOCs to make their profits is by earning performance bonuses (cancellations, punctuality, cleanliness, etc) while having all ticket revenue flow straight into a single national pot.
I do agree with the OP though that there has been vast, undocumented, fare rise on GWR. When I first went to university (21/22) I would buy Advance fares the day before travel, and they would be cheaper than a Super Off Peak return. Now the advance fares don't even undercut an Off Peak return when I try book 2 months in advance. Even looking at trips on Bristol to London an Off Peak ticket is cheaper, 2 months in advance.
In my opinion this isn't political. The GWR network has seen huge fare increases by stealth. That's something that needs to be called out, because changes like that should be justified if they are made. Especially given the LNER trial, because they didn't increase quotas there, so if GWR did bin Off Peak tickets on intercity routes the increases would be huge.