Would not say dying, more adapted. For several reasons, such as increased tempo and athleticism of the game and different requirements in a role, you will see a lot of players, that woud've been called trequartista's in the past, playing in different roles. You have those that became forwards or wingers like Messi, Giovinco and Jovetic, who you could say were already preceded by the likes of Totti, Del Piero and Baggio before. Although that is a a giant and (somewhat) false leap in history.
Then you have those that adapted to become midfielders instead. Consider the likes of Modric, Iniesta, Hernanes.
But as you said, vice versa you have your midfielders who adapted to palying the 3/4 role, to match the changed game. Consider the likes of Hamsik and Gerrard to your Boateng and Guarin(Bradley and Vidal, I would not consider to be so).
I honestly beleive Spaletti in his Roma time preceded or ot least illustrated a lot of these changes. Totti, a 3/4 as striker. Perrotta a battling midfielder as 3/4, Vucinic, who has a lot of 3/4 characteristics as winger. And Aquilani and Pizarro as midfielders instead.
So perhaps one could conclude players have become a lot more universal and less specific or less specialistic.