Purple Orange
On Moderation
The fact that they're even using XC? Using other TOCs with a change of train is mostly quicker than using their services at all (which is good, as I will do more or less anything to avoid using them as they're rubbish), but some people value a direct journey, either due to simplicity, or because they have a lot of luggage, or because they are elderly or infirm.
In particular a change across London is a right faff. People on here are I suspect likely to enjoy it, but "normal" people won't.
But in the case of HS2 and XC there are not many journeys that require a change across London that don’t today. The only difference will be that the journey via London to Basingstoke, Southampton & Bournemouth will be significantly faster than XC. I’d say the reason people don’t make the change is because London is a hassle, but not worth the minuscule time difference compared to the direct train.
However a change of trains in Birmingham or at OOC is a completely different situation because nobody will be needing to do much of a transfer. Northern destinations to the south west can change with a 5 min walk to the Moor Street platforms. People travelling from northern cities to Oxford & Reading will just need to switch platforms at OOC.
To my mind, sitting longer on the train is very much an enthusiast thing to do. Personally the least time I am on the train, the better and I’d argue more people value their time in getting from A go B than they do trundling on a Voyager at snails pace through York then Leeds, then Doncaster then Sheffield....