Perhaps because by the time they appeared in greater numbers on the allied side it was the Germans sitting behind minefields being assaulted, those on the defensive don't have quite the need for crossing minefields, but get progressively better at laying/covering those fields. As the Axis certainly did, and had to.
There's a few interesting Minenraumers that were developed but off the top of my head they're all roller or crushing types, maybe a few ploughs (?) but that approach never seems to have gone far in the period.
It's something of a dream of mine to see a restored Sherman Flail on the go, I chatted to one bloke last year that's got most of one (possibly East of England Tank museum, or maybe the DD Valentine chap... can't remember). He said he'd like to run it on Chesil beach one day.
(For those not familiar with Chesil, it's very long and covered in pebbles)
Cheers,
Adam.