Stalled development . Mmmmmmmmmmmm.
You seem to enjoy decrying everything UK made at that time , rubbish & Gardner daycab heaps , as in your last post .
If we look again at dates ,almost everything made back then had a much longer production life than now , where vehicles get a facelift almost every year , & a complete revamp every 5 or so .
Back then , things progressed much more slowly , the longevity of designs & also no doubt , the development time of new products .
But these rubbish heaps as you keep referring to , were the workhorses of British road transport at that time , & as such were more than capable & mostly reliable .
As I said in a previous post , manufacturers were certainly not as customer focussed as today .
But surely the operators cannot be held solely to blame , merely for purchasing what was available . They can only purchase what is made , if no Detroit powered Aerodyne equivalent is made , then it cannot be purchased .
If no manufacturer updates their designs , & continues to make old school , then that is what will be bought , & as other newer type imports arrive & appeal , then these will be bought in place . This is a manufacturer issue , not an operator one .
As an aside , in the Leyland story , was there a case they should have been more ruthless dropping old names in their make up earlier ( AEC , Albion ,BMC , Guy , Scammell , & concentrated on one or two identities , with rationalised production facilities . This may well have saved money , which may have been more beneficial in research & development.