I just checked transfermarkt.de and found only 2/13 teams that I mentioned as strugglers have made a transfer in an ammount of 1M EUR or more:
-Villareal (Asenjo - 5M J. Dos Santos - 2 M)
-and Celta (P.Hernandez - 1,6M )
Also Malaga paid 0,8 M for R.Horta and Eibar 12.000 EUR for J.Lara
And thats all of the paid transfers so far.
Barca in the meantime already spent 143M and Real 110M. Atletico also spent a lot -58M.
This is just one of the points of how unbalanced this league is.
Of course the english teams are taking players from Spain, but they are not taking them from Barca, Real as they aren't in this league. As I said the only good thing about spanish football is the ammount of talent and quality players produced for the market - Real,Barca and English teams in majority of the cases.