Ha. I shall be very keen to monitor my train back from Bournemouth this afternoon to see whether I have struck lucky again with a Marie Celeste train. What do we reckon the odds are?
Firstly, you seem to have ignored
@Bletchleyite's point about Bournemouth being at (almost) the far end of a line which is much busier at the other end. A fairer comparison would be to something like many of the Virgin trains I've been on where north of Lancaster, you could easily accommodate everyone on a smaller train. But the point of the long train is that it's absolutely packed south of Warrington - just as the Bournemouth trains will often be very busy east of Woking.
But secondly, there's another way of looking at the Bournemouth route: As a perfect example of suppressed demand due to poor timetable and connections. Bournemouth station is nearly a mile from the town centre, and - unlike Manchester - there are no frequent trams to get you to somewhere more useful. If you're going to London, the fastest trains take nearly 2 hours - almost the same time as Manchester to London, despite Manchester to London being twice the distance. Looking more locally, there are two fast trains an hour to Southampton, which must be the nearest major destination from Bournemouth. Except that's not every 30 minutes. Coming from Southampton, the two trains depart 6 minutes apart, leaving almost an hour gap until the next fast trains. And if you live at one of the local stations around Bournemouth, you'll see one or two trains per hour. If it's 2 tph, it's still with gaps of up to 50 minutes because the trains aren't regularly spaced. And these are mainly stations in fairly well built up areas. And in case you want a really extra-slow journey, the hourly stopper between Southampton and Bournemouth waits for an astonishing 25 minutes at Brockenhurst. If you wanted to deliberately design a timetable to stop people wanting to travel by train, despite high notional frequencies, the timetable around Bournemouth looks almost perfect for the job!
Oh, and the longer trains divide, losing half their carriages to go West from Bournemouth. If I recall correctly, that's not because of any particular desire to do so, but because the power supply west of Bournemouth isn't adequate for longer trains.
Can you see where I'm heading... you can construct a pretty good argument for saying that trains around Bournemouth would be a lot better used with a bit of investment to improve services. Exactly the same argument that is often (quite correctly) made for many services in the North of England.
I'm not saying this to have a go at the North or put one part of the country against another. The point is that there are almost no parts of the UK that couldn't benefit from improved services or investment in rail infrastructure etc. - and it's therefore pointless trying to make an argument based 'you shouldn't get anything because we really need it'