If I add spectating, servicing & timekeeping I've been involved with 33 of them since 1977 and 24 Nationals. I reckon I've spent around six months over there on rallies all told!
I think you're right, and I very much doubt that Ceredigion can offer the kind of financial incentives that the Manx could in its glory days when they struggled to attract top level Eurpoeans. The Manx did get some Europeans over, lower down the entry list. Most of them came from Holland and Germany (competitors & marshals), usually people involved with the West Euro Cup. They also managed to get the French Citröen AX Cup competitors over in 1992 as their "foreign" event, so again not premier league.