I think this whole sorry episode shows that what are supposedly simple solutions often turn out to be anything but, and what looks good on paper when bidding can be fiendishly difficult to deliver.
I've had some insider info on this from a former boss who has been quite widely involved in rail franchise bidding, and the main driving force behind this whole project was someone on the bid team who is, I believe, long gone and therefore not having to deal with the day-in, day-out consequences. Apparently they were an HST enthusiast who ignored advice from others suggesting it was a bad idea. A fairly catastrophic error seems to have been made early on regarding the running costs, apparently based on only one power car!
I think a lot of people have defended all of this based around the idea that LNER services are much more popular, therefore ScotRail needed to up their game. Agreed, that's absolutely fine, but I think the assumption has been made that "people prefer LNER services because they're HSTs", and therefore it's been decided that HSTs are the best solution. I would suggest that 99.9% of people don't know or care what HSTs are, and that the real issue is that "people prefer LNER services because they have more seats, more space and better catering, which HSTs are able to provide." However, HST's are not the only trains able to provide this - there were a whole heap of other solutions. Abellio has now been running the franchise for four and a half years! They could easily have had new stock in service by now, even if there were delays!
Many of us in the industry could see this coming. I've worked with another company that operated Mark 3s until fairly recently, and they're in absolutely terrible condition, however smart you manage to get them looking on the outside. They're now somewhat beyond their design life and are suffering from terrible corrosion, and a whole heap of issues with obsolete electronics. I also question this unshakeable belief among enthusiasts that they represent the absolute pinnacle of rolling stock evolution. They don't - they've always had a number of flaws that are quite annoying, and while the power door refurb deals with some of the most significant ones, it certainly doesn't deal with all of them. On top of that, the power cars are noisy and polluting compared to more modern stock, and ScotRail have taken on the most unreliable sub-fleet of the lot.
I've been saying a lot of this since the beginning - it was an absolutely dreadful mistake, and I'm not surprised in the least that it's gone so badly.
Just order something new, FFS.