IS THE TARGET MAN BECOMING LESS EFFECTIVE???

Absolutely. Aside from Barcelona most of the top teams in the world play with someone big and / or strong upfront
and then build off him.

Gomes
Mandzukic
Lewandowski
RVP
Dzeko
Tevez (Not tall as such but as strong as on ox and one of the best at holding the ball up and with his back to goal)
Ba
Benzema
Ibrahimovic
Cordoza
Falcao
Diego Costa
Vujkic

Thats just off the top of my head of players playing for big clubs