Hmmm, I don't really agree with this.
I actually think fullback has more depth than any position in the NRL.
For instance:
Stewart
Dugan
Hayne
Slater
Inglis
Hiku
Tuivasa-Sheck
Gordon
Locke
Barba (Admittedly horribly out of form)
Milford
Hoffman (could play fullback)
Tomkins
Tedesco
Are all class players. Name one other position with that much depth.
Penrith have Moylan who is a star of the future. Dogs have Perrett who is average, Cowboys have Morgan who is average, and Titans have Zillman who is very average.
With than in mind spending huge money on everything except the very, very anything except the top drawer fullback is madness. And by top drawer I mean Slater, Inglis, and Hayne. The modern game is built on second man plays. It gives fullbacks a lot of space and makes them look like superstars. Sure we need a good fullback, and certainly someone better than what Rowe has shown us - though he's certainly improved in certain weeks.
Let's just remember Tedesco didn't look amazing when we were very ordinary last year. For all we know if you slotted someone like Hoffman in for us this year he'd be going as well as Tedesco has.