If you can find me any evidence that they offer a realtime tracking service with the "signed for" scheme, then I will accept your analogy. Until then, I would say you need to realise they are providing the service they claim to provide, the parcel is signed for at the destination, the notification of delivery is logged and available to be viewed online within 12 hours of deliver, and the proof of delivery (signature) is available to be viewed online within 48 hours of delivery.
Whoever radiospares are/were, and whatever service they offer is completely irrelevant. If they are so fantastic, use them instead. As I say, the Royal Mail, to my knowledge, have NEVER claimed to offer realtime tracking, and none of the MAJOR delivery companies within the UK do so far as im aware (ive not experienced all services from all companies of course, but a fair few at least). I doubt radiospares are handling in excess of 30
BILLION items per year, and I doubt they use moe than one or two isolated and fully automated distribution centres etc... I also doubt they would compete on price if their service was nationwide. In addition, it sounds like they upgraded their one or two distribution centres, how many billions and how long would it take to upgrade Royal Mail's hundreds of distribution and handling centres, and thousands of sorting offices, and would you be prepared to pay a LOT more for deliveries just so one or two people can sit in front of their PC screens like simpletons, watching their item going down the conveyor belt, watching their items being loaded onto a van etc...
Besides which, most of us just want our items delivered, and don't have any interest as to how they get to us.
In an ideal world, everything you are looking for would be in place, but we don't live in an ideal world, and everything you suggest would have to be paid for... and dare the Royal Mail ever try to introduce such systems, then the Labour Party (sorry Unions) would be trying to stop deliveries altogether until the proposals were dropped. Royal Mail are lagging behind the times, and they are the first to admit it, for the simple reason the Unions do everything in their power to prevent them from modernising.