I started watching football in the late sixties and I don't recall any pre-match warm ups taking place on the pitch.
May be the mists of time but I don't recall if it was a thing then or when it became one. Any ideas?
Lots more hammys and quads pulled though

Probably more just to do with the adaption of time at a guess. Accessibility probably being one thing and the other being the bridging of semi-pro attitudes; filtering those out in favour of an ever growing professional and elite sport.
Most pre-match warm ups in the 60's was half a pint of milk stout and 6 fags wasn't it?