An imaginary company theoretically taking over Lyneham to develop it as a never-going-to-happen regional airport wouldn't give a monkeys about infrastructure per se. It's all about land and existing usage of said land. Bristol doesn't have a hydrant system and gets by quite happily with bowsers. BFIs would ultimately be renewed anyway if and when a fuel hydrant system became necessary.
Bristol airport has the worst road/rail links of pretty much any regional hub in the UK (along with the smallest runway) and yet it is still able to exist as a viable economic entity. In this fictional construct of ours, I reckon that the Fat Albert Memorial International Aeropark & Burgerama (Lyneham Intl) would actually, given the right financial conditions, be a very viable proposition.