I think it depends on your definition of a top tier player. Are these the world class players? If so, what is your definition of world class?
For me, a world class player (or top tier) is someone that wouldn't look out of place playing for any club in the world. That doesn't necessarily mean that get in that clubs first team as it stands either, it means they wouldn't be out of place at such a club. For example, I club could have Aguero, Suarez, Messi and C.Ronaldo in their ranks but Neymar or Bale wouldn't out of place if you swap them with any of those names. Its not about comparing other players because they could be playing in a time when we are blessed to have a abundance of talent. Messi and C.Roanldo are the perfect example of this. Both would be classed as the outright top player in any other era but they happen to be playing in the same time era.
Liverpool NEVER sign a top tier world class player. I can't recall us doing so in the last twenty years, maybe the last ones were Kenny Dalglish and/or John Barnes. We buy players that have something to prove and skills to develop. We buy players to have their best years with us, we don't players because they've just had them.
Take the crazy Andy Carroll deal out the question and we've never spent over £25m on someone. That's pretty crazy for a club of Liverpool's size. Especially when you consider our biggest rival was regularly doing that over ten years ago. Its not that we never had the funds either, we've had them. We just prefer not to buy the already made and proven superstar IMO.
I try and steer clear of what is world class. There are some we can all agree about and then there's the debatable ones. I'm not saying you should be getting the best in the world. For example, IMO Sanchez, Reus, Godin, Garay, Greizmann are already top players but not world class. All in positions Liverpool needed and all players Liverpool should have gone whole heartedly for. Sanchez I understand you did, but I don't know why it didn't happen. However it shouldn't deter you.
Just regarding your point about players that wouldn't necessarily get into a side but that wouldn't mean they weren't world class. Imagine if Rooney was playing in the 90's. Not saying he's world class by the way, but would he have reached 100 caps with the likes of Shearer, Sherringham etc? Hmmm...
