It's true Arriva have had a lot of external problems to deal with. But most of these have been entirely predictable...
Electrification delayed? Who'd have thought?
Government backtracking on investment plans? Inconceivable!
New trains with reliability problems? Literally the first time that's ever happened.
Rail unions vehemently opposing downgrading roles? Why ever would they do that?
Ambitious new timetable falling apart? Never heard of anything like that before...
The basic problem appears to be that the plan for the franchise required all these issues either not to occur or somehow to resolve themselves. It is entirely predictable that they happened. Failure to plan for this is a failure of management.
Arriva is still failing to provide a basic reliable service. It is not 'slowly improving'. The reliability stats from 2016 show consistently worsening performance. There was a particular dip in summer 2018 but this is superimposed on a general decline. This is backed up by the anecdotal experience in my area. The Airedale and Wharfedale lines to Leeds used to be pretty reliable. Cancellations were rare; delays usually only a few minutes. Largely unaffected by timetable changes, it would be expected that the service should have continued as it has done. However, cancellations are now commonplace, with peak morning trains cancelled multiple times during a single week. PPM and right time stats are significantly down. It's now at a level when you can't trust a train to turn up; that's a real problem. And this is for a part of the network which hasn't been subject to major timetable overhaul or delayed infrastructure. Arriva have to take responsibility for this.
I hear many voices on here giving a counsel of despair: 'nothing can be done', 'it would be just the same with someone else' etc. This is demonstrably not the case. We have seen failing franchises before (Connex, Arriva Trains North - first incarnation, National Express East Coast) which have been significantly improved by their replacement, whether they be private or public.
Particularly for city commuter networks, it seems that direct public ownership (London Underground) or concessions (Merseyrail, T&W Metro, Overground, TfL rail, pretty much all light rail) are reasonably successful arrangements. I don't think a merger with Transpennine would be a good idea; management focus would inevitably fall on the premier routes to the detriment of others. Governance arrangements also need to be simplified with full decision making and budget holding at regional or city-region level.