There's a combined number of about 20~ certified world class players of French and Portuguese origins within the past 20 years or so. About 2 or so of them ended up on our team, and one of them was past their prime. Several of the best players in the world are of either Portuguese or French origin. Pick a combined France and Portugal XI, replace them with our current squad and we'd be the best team in the world. The countries aren't the issue, the scouting network within these countries for this club and squad building is.
Shit like "stop going for French players" is so unbelievably stupid. Griezmann was world class in Atletico, he's not with us, because we require #9s and second strikers to play in a way that's antithetical to his style of play in Atletico. From Eto'o, Villa, Messi, and Suarez; they all presented immense individual ability to play make, drive the ball, be versatile, and take the game for themselves. Whereas with Griezmann, his optimal style of play requires him to consistently play off others, he needs to have a specific role with limited versatility, he lacks speed and dribbling ability.
There is no curse or jinx, there's nothing wrong with the players coming from these countries; the club just needs to do a better job of finding the best players suitable to the squad's needs.