English is learnt by all, as a first or second language, and all documentation/signage is in English as well. You need it to survive in modern UK and it gives you an edge internationally as you alluded to. So why would we not have English?
However I do think Welsh needs to be coaxed along. I am part of the problem really as I have no great Welsh ability, growing up near the border and with English the most important language on a practical level, but if the Welsh language were to disappear or deteriorate further I think that would have a nasty knock-on effect for the culture.
It does annoy me when people seem to portray the speaking of Welsh as an act of treason however. Only the other night, the GF of a flatmate was going out to work when they expected a lot of Welsh to be on the wazz after a few sports games here. She said disgustedly 'Oh and they all speak Welsh to each other' as if there is somehow something wrong with a Welsh person speaking Welsh to another Welsh person when in Wales?
Also the typical student rumours of 'don't go into that pub (with the Welsh name) as you'll get started on for speaking English' when in fact they're happy to have you (but no one would know that as they'll now not go in)
Not saying there aren't rude Welsh around, but I do find that some impressionable people over-egg this somewhat and deduce that we all hate the English undyingly
