At risk of bringing this back to the original posters point...
I think we're just as good as anyone else at coaching youngsters, everyone has natural attrition of players who look like they will make it but don't. Even Wigan have had quite a few of those, Shaun Ainscough anyone? St Helens have had a lot, Ste Tyrer was going to be the English Matt Gidley. I'm also happy with the bedding in approach we are taking, it's not a "Big Bang" where you throw a kid in and it magically works and he's a first team starter for 10 years. It takes time for them to acclimatize and that's what we have done this year with a lot of our younger players. Hadley for example, probably isn't ready to play a full season playing 80 mins a week, but I would expect next year his game time will again increase from this year.
It's a process we all need to accept takes time, for the good of the club and players.

Who said that? Where is your evidence to prove who spends what on academies? Basic facts are that we aren't as good as some teams at producing our own top class players. The reasons for that will be complex and will, undoubtedly include finance but that wasn't the point the poster I replied to made. Now if you can come up with some evidence that our academy produces players as well as every other club in SL then I'll happily admit to being wrong

A very good question posted by the OP, but I will expand it.

Is it about the coaching ability or talent identification.

Are we reliant on signing quartile 1 players and persisting with them and trying to turn them into SL standard as opposed to the late developing quartile 4 players who are proven to have more success when it comes to the talent pathway, especially to Elite level with England.

Q1 players stand out at youth, usually in dominant teams so naturally people presume they will go all the way, sometimes this is to the detriment of their core skills, be this down to poor coaching or the players thinking they do not need to learn as size and speed overrules.

The RFL are looking at this and have brought out new programs to address this but it will take a lot of time and belief, plus an education in certain peoples thought processes.

The other issue is if these players have developed coping mechanisms for the more intense physical contact they will receive, something they might not have done whilst bring in 'great teams'. And ability to be able to handle defeat or how to win games from a negative position and do things the hard way.

I will give you that we haven't been good enough over the past years (and keeping them) but I think in the last 2 maybe 3 years we're getting there - i.e since Agar left.
Creating international players isn't a measure of success, I'd say players playing in SL/NRL is a better measure. If we take that, even in our "darker" Agar days we've created a number of players through our academy, Tommy Lee, Scott Wheeldon, Danny Washbrook, Reece Lyne, Tom Briscoe are all playing SL regularly albeit elsewhere. Wasn't there a thread on here mentioning how many players are now playing SL regularly who used to be at Hull.
And for players playing at Hull through our academy, Danny Houghton, Tom Lineham, Chris Green and Bowden are first team regular, Hadley pretty regular, Shaul played nearly every game last season. So I don't think we're doing too bad if you don't purely search for Internationals.

As for internationals, we have created at least 2 internationals from our academy recently, Josh Hodgson (granted he left) and Tom Briscoe. Seen as you said since SL started Horne played international, Yeaman did, Paul King (Token app for England I think) Cooke should have.

Tom Briscoe was effectively always going to be international standard when he came to us..he wasn't far off aside from fitness & a bit of experience, we certainly didn't 'develop' him. His innate abilities were there to see at 17, power/speed and a decent amount of pluck..just not that smart/thinking ability which still shows in his mistakes, the same ones that he's been making ever since he came on the scene.

That said, creating international standard players from your youth set up IS a measure of success, the statistics back that up. to ignore those quite obvious facts is just crazy. yes we've had some very decent players come through our system..that's the law of averages and once in a while a gem turns up. That said we've had far too many 'prospects' turn into average players.
Washbrook was going to be the next club captain for years to come..our amazing coach at the time put paid to that, Houghton has been a very good player but has never kicked on, Yeaman had all the tools aside from a brain and did pretty ok with them in spells but goes missing far too often. Cooke/Horne are the best youth system players we've produced in the last 15 years.
Certainly Hadley, Green, Lineham & Saul [icould[/i turn into top notch SL players, will they step up to international grade.. the odds are against them for sure.

Answer to the question asked. Yes we have hopefully time will tell