I don't think those train fares are unreasonably low. Don't forget that, in the main, the towns surrounding Glasgow are not affluent and local residents don't tend to be well off - so fares will tend to be lower than in more affluent areas anyway.
Just to give examples of journeys which are of comparable length elsewhere in the country - an off peak day return from Newcastle to Sunderland is £3.70, from Cardiff to Barry £3.90, and from Liverpool to Meols Cop (just beyond Southport) is £5.50. I've deliberately picked urban areas which aren't especially affluent as I think that gives a fairer comparison (though Southport is fairly well off so that particular choice might not be perfect).
In general, buses can't compete with trains on fares, at least not on these relatively short distances. They have to focus on frequency and convenience - they stop more, they penetrate estates more effectively. As an example, the X24 between Sunderland and Newcastle is more expensive than the train or metro, but is well used because it connects the west end of Sunderland to Newcastle (avoiding the need to travel into the centre and out again). That's how you compete - and there do seem to be routes which do this quite effectively (the 18 in East Kilbride for example - I expect Calderwood residents will choose that bus over travelling to the station and then a train).
I'm fine with adult train fares being subsidised to those kind of levels - it's just that we don't then consider the need to subsidise adult bus fares (children, pensioners, sure, but not working age adults)
So of course people will prefer the train, since they can travel all the way from Glasgow to Paisley/ Hamilton/ Airdrie/ Dumbarton etc for the same price as a three stop bus journey.
The reason why you can say that "buses can't compete with trains on fares" is because train fares are so heavily subsidised in PTE areas, whilst adult bus passengers are having to pay the full fare (in fact, are often having to pay more because of the way that bus companies have to "game" the system to cover the cost of carrying so many concessionary passengers).
I'm sure that trains would be more popular if the fares were identical, but we're in this strange situation where adult bus passengers are having to pay more than the normal fare ought to be (because of the way that Concessionary fares are rebated) whilst adult train passengers are only paying a fraction of the fares (because of PTE subsidies). No wonder buses can't compete.
Or we stop giving away as much free travel and start subsidising concessionary fares properly (rather than this silly, no better or worse off thing which doesn't actually work) so then bus operators aren't constantly playing a game against an algorithm to get decent concessionary reimbursement.
The tweet got removed relatively quickly but I'm sure Ralph Roberts said a while back on Twitter than if concessionary reimbursement was at 100%, McGills could offer a flat fare of under £2 on all routes (it was a figure between £1.20 and £1.70 but I can't remember fully so I am opting for under £2 incase someone can find the old tweet). When bus operators fares are based on playing against an reimbursement algorithm, it will always mean that fare payers are paying much more than needed to counteract the money lost through the 'no better or worse off' concessionary passes.
Yeah, it's really frustrating - I don't mind old people getting free bus fares in principle (I'm hoping to be old myself, one day), but bus operators have to overcharge adult passengers to ensure that the councils give them a "fair" rebate (whilst the same councils subsidise adult train fares)
It will be impossible to produce a business case for the Glasgow Metro without proper bus integration. You can't continue to have buses from all over the Strathclyde region come into the centre of Glasgow if there will be street running trams on the core cross-city routes. Preserving the bus network could only be done if the Metro had extremely expensive underground tunnels in the city centre, which is unlikely when street running capability is almost guaranteed for ease of extension into lower-density suburbs.
Encouraging bus passengers to interchange onto the Metro is also a great way of boosting passenger numbers on the Metro from day one. With fewer buses, the Metro can then run faster, reducing journey times again. Heavy rail services can do the same.
What this seems to be is the private bus operators shifting into acceptance of a franchising model like in London. There will still be plenty of work for all of the companies, taking on bus route contracts from SPT or its successor.
I appreciate that there are arguments in favour of and against the idea of terminating bus services at the nearest light rail stop (e.g. here in Sheffield the Stocksbridge buses have been largely replaced by a tram feeder service from Middlewood, but Stagecoach weren't able to create the same market on the SL2 from Malin Bridge to Stannington or the SL3 from Crystal Peaks to KIllamarsh - both of which were scrapped).
However there does seem to be an attitude on the Forum that "we must maintain long distance railway links because people don't like changing" but also "long established bus routes must be cut at the nearest heavy/light rail station to force everyone to change to get into the city centre"
So train passengers get to retain their direct services but bus passengers should be made to change modes. Not a go at any one poster in particular, but I've noticed a number of times that rail passengers are too important to have to cope with the inconvenience of changing en route whilst it's apparently okay for the bus routes to have such cuts.
Now to be fair, The motorway system around Glasgow was going to get built no matter what, lets not forget how bad the old A77 was and how clogged up the south side was with traffic heading to Ayr. Stagecoach Glasgow did rather well out of the Motorway system with the likes of X8-X10. First's Busiest service No1 uses the Cyldeside Expressway. It can be double edge sword.
The M74 extension doesn't have any buses on it, does it?
The various bits of urban motorway/ dual carriageway mean that it's much easier for motorists to access places like Silverburn/ Glasgow Fort/ Braehead (even if travelling from the other side of town) - which makes it very hard for bus operators to compete.
Compare that to Edinburgh, which has a pretty similar urban road network to fifty years ago (other than the little routes like the Western Approach Road and Harry Lauder Road), and buses can still compete for urban journeys