What genre is prog's foe ?

There are definite cross-overs between punk and prog, and have been from the off-set. And there was certainly a mutual respect and admiration between many punk and prog musicians in the '70s.  (Not all, obviously, and it was the detractors the media pounced upon. It's easy, for example, to make fun of Yes.)

As punk became post-punk, it became even more prog than some of it already had been. And while punk exists still, it tends to be vastly different from punk then - simply because, especially in the UK, punk was as much a culture as it was a genre. A lot of early American punk was actually pretty much the equivalent of prog music of the US (as discussed in the American prog thread).

I don't think it's really possible for any genre to be a foe to prog, simply because prog isn't a genre in itself, and can exist within any genre. I am quite sure one could find examples of prog in every "genre" given in the poll.

I think the biggest foe to prog is probably actually prog itself - it is its own worst enemy. Or, at least, the gatekeeping and infighting of its fans are its enemy. Potentially, some might say that the rise of retro-prog is the foe of prog. I don't think that's necessarily so, as there can still be some really innovative and original sounds made under that label - but certainly a lot of retro-prog does nothing to help the image of prog in the eyes of those who don't know much about it.