SpaceCruiserSun Tzu Ideally Swansea, Cardiff and Wrexham would play in the Welsh League but it's not reasonable to chuck them out of the Football league.
IIRC, when they were setting up the new Welsh league (in the early 90's I think?), they asked the big Welsh teams if they would defect to the new league. Rather predictably, the big Welsh teams turned it down because they would lose money if they played in that league. No surprise at all.
Very sensible on their part.
I suspect the fact that the standard of football would be somewhere between parks and school playground also came into it.