Liverpool have signed Robertson from Hull, Tony Gallacher from Falkirk, Danny Ings from Burnley (when in Championship), Gomez from Charlton, Bogdan from Bolton, Adam from Blackpool, Danny Ward from Wrexham.
Same year that Lallana was hidden from everyone, buried in league 1 Liverpool signed Shelvey from err league 1 Charlton.
There has been over 100 transfers from lower league to premiership clubs last few years.....
But you're probably right. Our players were invisible until Cortese left.