Most players learn the most in there teenage years, and by the time there 17-18 you can usually tell if there going to make it.
Ronaldo learnt alot from us, as we aquired him 4 years earlier than you did Lampard, though he still would have learnt alot more with Sporting Lisbon.
You aquired Lampard at the age of 22, and paid a fair bit of money for him at that time. He was already a quality player, he was just able to shine more with you guys as there were better players around him. You just benifiyed from all the hard work the West Ham academy put in with him.
Though West Hams academy has proved pretty good over the years, producing the likes of Rio, Carrick, Lampard, Defoe, Johnson, Joe Cole among others. It's probably been the best academy in London over the past 15 years