Whatever the reason for their being different styles of cycling I am not sure, but there seem to be different styles.
In my field of cultural psychology there is a theory (
Tomasello, 1999) that there is a "ratchet effect" in cultural transmission and evolution such that once e.g. someone has worked out how to use a stone, then a stick with stone attached (i.e. hammer) to bash things with, these tools, or techniques tend not to be forgotten.
It seems to me that the "French" (ankling, cycling in circles, bunched up at the back, push pull, glute intensive) style of cycling is one which, despite the ratchet, I was in danger of never acquiring. The ratchet had, for me at least, slipped.
I am very grateful to say however that thanks to a few words by Greg LeMond, and some posts here by Carbonfibreboy (especially the one that suggesting using the glutes from the 5 O'clock position) however, the ratchet is working. Phew. Thank you!