Sadly last time I looked it's mostly down to what 4468 says ^^...
The days when BA to threw cash at a problem to solve it have long gone; a year or more back they
wouldn't do it, now with cashflow as it is my guess is they feel they can't do it.
I can't speak for EDI itself but that line of thought has meant the demise at many station of the likes of the dedicated BA uniformed/badged station manager rog747 describes, many of whom took pride in ensuring "their" station performed as well as possible and certainly would be straight onto the GH if their flight was delayed inbound and/or outbound.
As for the PA's...I'm fully in alignment with those that hate s
elf congratulatory PA's (and I was always aware you were holding yourself hostage to fortune if you started predicting an early arrival too soon) but the teaching at BA certainly was that in unusual situations the passengers need to hear something from the front end on a frequent basis, even if the something was "I have no news of an improvement in our situation".