In the comments to Television Q and A, Piers Beckley writes:
"Riffing off the technology point: Lew Grade's ITC stuff from the 70s was shot in 35mm with a view to worldwide sales. And the thing about 35mm is that you can even now remaster it into blu-ray and other hi-def formats... (snip) Record your show in a sensible format and you've got an archive, something to build on. Sure, it costs more, but you make your money back five or ten or twenty years down the line."
A term in vogue for a while - I forget exactly when - was 'futureproofing'. The idea was that you aimed for the highest technical standard you could achieve, rather than the one that prevailed, in the certain knowledge that the prevailing standard will quickly date. Hardly a new idea - Richard Greene pressed for the 1950s Adventures of Robin Hood to be filmed in colour rather than black-and-white, which would have given them a broadcast life to this day. Within the past couple of weeks I heard that the all-colour Thunderbirds is to be remastered, repackaged and relaunched yet again.
But TV execs are like politicians. Less interested in long-term benefits than immediate ones. I can remember ITV huffing and grumbling about shooting a drama in widescreen even though 4X3 was patently on the way out. They cared only about next week's ratings, not long-term value.
(In the end they compromised on the awful 14X9, which was no use to anyone even then.)
But couldn't you weep to look at something like The Jewel in the Crown now? Such an enormous enterprise, and all that talent... all in a little square, and seen through a sock.