Sorry, I don’t think I understand what you’re asking…? Are you wondering why visitors from the US to Wales didn’t know any Welsh? I think it’s probably true of most visitors to Wales, from England or Scotland or France or anywhere else, isn’t it? In general, I think people are reluctant to try saying even a few words of a language if they have no clue how it’s pronounced. As a group, I don’t think non-locals do much better at trying the local language when they visit Slovenia or Thailand or Morocco (based on my experience in all three places).
I wish that Wales, and specifically the Welsh Tourist Board / Visit Wales, did a better job of marketing the Welsh language as (a) very different from English (most non-Welsh think it’s likely a dialect of English, which wouldn’t be surprising given geography), and (b) a huge ASSET to Wales, and a fun thing to encounter during a vacation there.