Old, well late middle aged(!). Wise, well wise enough to have got out of the rat race but any wisdom I do have is more in terms of knowledge and hard won experience.
I firmly believe that BA will eventually withdraw totally from Sussex Regional aka Gatwick. The reasons are myriad if you look closely at BA's philosophy.
As for Prestwick, I don't understand your premise. SAS, KLM,TCA/Air Canada, BA, Pan American only needed PIK (and SNN for that matter) when they needed to refuel.
I don't recall SAS and KLM having fifth freedom rights ex PIK - though AC and PA did.