The costs of setting up an outstation at St Albans would be negligible when the main focus of splitting the 724 is to eliminate constant late-running. It must be having an adverse affect on Arriva's total punctuality if it continues at this rate. Furthermore, driver's hours is a non-issue, considering (and I'm assuming this is the case as I only travelled the Heathrow-Watford section both times) that drivers swap over at St Albans, which explains the 'technical split' there, so there's little difference to the staff roster. If anything, it should help concentrate resources within either sections.
Again, is there a large number of people willing to travel all the way from east of St Albans to Heathrow? Even for the tempting £2 single fare and the 724 being limited stop, the slow radial route would be no match for Hatfield, Welwyn, Ware or Harlow when taking a train into any London termini and thereon Crossrail is quicker and more frequent. As for radial journeys between Hertford and Watford and the like - again, I wouldn't guess a huge number would travel by bus, given the M25 conveniently parallels the 724.
No, drivers do not swap over at St Albans. Arriva has no presence in St Albans apart from a number of routes passing through. Drivers from Harlow go to Heathrow, have a break and return, that is their work for the day. The 'technical split' is just maximum length of route nonsense. At the moment the route is just the right length for a driver's day to go there and back.
Looking at the routes one might think that it would be better to stick the Rickmansworth to Heathrow section on the 725 rather than the 724. But at the moment the 725 does Stevenage to Rickmansworth and back in a single shift. If you extended to Heathrow you'd have to have a break at Heathrow and then return, to fill out a whole working day then something else would have to be added at the Stevenage end before or after the shift. And on the 724 you'd need a break at Rickmansworth and then add some extra work before or after at the Harlow end. Very complicated.
In the old days there were a number of Green Line routes across London which worked on this basis, the most straightforward ones being base garage - London- far end garage, such as the 714 Luton-London-Dorking. A driver drove to the far end, had a break at the canteen there and returned home. Generally 16 journeys a day with four vehicles and eight drivers from each end. The 724 is about the only route remaining which runs one end to the other, then a break, then back. The 724 is all from a single base which only works because it is a 24 hour service, the 01.05 from Harlow seems a weird time but when it returns it will be providing morning rush hour services into Hertford and Harlow. There isn't any other Arriva depot sensibly placed anywhere near the western end to split it up, the cost of setting up an outstation in St Albans would be totally disproportionate to the benefit.
In London Country days the 724 was originally Romford and High Wycombe, later Staines ran it at the western end when it was diverted to Heathrow and then Harlow at the east when Romford closed. Hertford may have been involved before it closed, I am sure Ware was, but I don't believe Hatfield, St Albans or Garston ever had anything to do with running the route. St Albans ran the parallel 727 for many years.
Yes it suffers from traffic congestion but I think there are too many useful links it provides across Hertfordshire that it is best left alone. It seems to work and carry passengers. The economic given the £2 fare - that's another story!
None of the route is in Bedfordshire - it goes directly from North Hertfordshire to Luton, the latter hasn't been part of Bedfordshire for administrative purposes since the mid-1960s.
Silly me - living in the past again! Not the mid-1960s I don't think but certainly some time.