Ospreys chief Mike Cuddy has revealed they failed in a £1m bid to keep star Perpingan-bound back James Hook.
Ospreys backer Cuddy warns that the likes of Hook and Lee Byrne could be joined in France by the entire Wales Test team within two or three seasons.
"In two or three years' time we could have the whole Welsh team... not playing in Wales," Cuddy told Friday's Sport Wales programme.
But pundit Gwyn Jones says Welsh rugby must learn to live with such movements.
Managing director Cuddy said: "We made James Hook a huge offer, had a sponsor in to make him an offer of over £1m to help us over three years and that wasn't enough.
"With the money that the French teams are pouring out at the moment unless we do something about it in two or three years' time we could have the whole Welsh team running out not playing in Wales."
Ospreys coaching boss Scott Johnson has pleaded for the Welsh Rugby Union to offer top-up payments to the nation's top players to keep them in Wales.
He has also demanded clarification of Warren Gatland's long-standing policy which is designed to discourage Welsh Test players from leaving any of the regions.
Regional Rugby Wales chief executive Stuart Gallacher has warned that the WRU is unlikely to be able to provide any extra funds.
And ex-Wales captain and flanker Jones says Gatland's policy was well-intentioned, but has been overtaken by events.
Ex-Osprey Gavin Henson is already with Toulon, Byrne will head to Clermont Auvergne after the World Cup in New Zealand in the autumn and Hook will be at Perpignan.
The Swansea-based region are also losing tight-head prop Craig Mitchell to Exeter while scrum-half Dwayne Peel is at Sale and fly-half Nicky Robinson is moving from Gloucester to Wasps, where number eight Andy Powell plays, in the off-season.
Jones said: "It [favouring Wales-based players for Test selection] was a good intention [by Gatland].
"I think it was a nice or a good thing to try to do, but with the modern market forces you can't compete with the teams in France, in particular.
"And Wales can't play without James Hook. I mean somewhere on the pitch he's going to play and if the next player, Alun Wyn were to go, or Adam Jones were to go are we going to say "no you can't play [for Wales]"?
"These boys have to go and earn their living and do the best that they can and I think it's just tough luck.
"We have to get on with it. Gatland's law was a good intention, but it's difficult to put [apply] in reality."
Watch an in-depth analysis of how the Ospreys have fared this season, Friday, 21 April on Sport Wales, BBC Two Wales, 2200-2230 BST.