"why was its influence not felt on Cotswold and North West morris"

This is only my rationalisation, but the Cotswold and North West traditions were both based on public display - in summer, in daylight and in front of large(ish) crowds - and primarily as a "show". the dancers would be proud to be recognised as they showed off their skills

Whereas Border tended to be done in Winter, at night, and primarily as a fund-raiser. The dancers would have more reason to seek anonymity, especially if the activity was generally regarded as little more than begging.