Doon frae Troon
Ryder Cup Winner
No it doesn't "need" Swansea or indeed any other non English Club. No idea why they joined the English league in the 1900's all those years ago but it seems they earned the right to be where they are right now.
For Celtic or indeed any other club to enter the football league then they would need to start from the bottom rung of the ladder and work their way up.
Will be interesting to see why Doon thinks a UK league is the obvious answer ? When it isn't needed for the English leagues
For starters the average attendances and TV money will be greatly increased,