Football is (or at least should be) meritocratic. There is a cycle, a food chain, and we are now at the top of it.
If an Italian player has 2 standout seasons in Serie A, Juventus will probably buy them. If a German does in the Bundesliga, more often than not Bayern will historically sign them. The Rags applied that formula to their benefit under Ferguson. It's the best policy to adopt where possible, because there is little chance that the pace/standard of the game in the respective country will effect them.
Without this opportunity, you'll never know how good a player is; Barry and Lescott were understated but crucial elements of our first wave of success. Neither had played for a top club before they joined us, but grabbed the opportunity with both hands, and to a lesser extent, so did Milner. By some of the derogatory logic on here applied to Delph, they'd never have been signed.
How many PL titles would Roy Keane have won if he'd stayed at Forest? Or Carrick at Spurs? Cahill at Bolton? How many Man Of The Match performances against top European opposition would Hart have had if he'd stayed at Birmingham after that sensational loan spell he had there in 09/10? None.
It's impossible to judge whether a player has top-class credentials until they've been given a fair chance to establish themselves at the highest level. Some take it, some don't, but someone like Delph is more worth of a place in the Manchester City squad based on his excellent performances in the Premier League over a sustained period than expensive failed imports like Anderson and Garcia.
This league is a tricky one, especially for a midfielder; the amusing failures of both Di Maria and Veron at Trafford's biggest club are testament to that. Both possessed world-class ability, and had years of elite-level football behind them but just simply couldn't get a grip of the game in the Premier League. There is a real possibility that Pogba would get found out in the same way, as both came with far better pedigree (the Serie A Veron played in was the best league in Europe at the time and infinitely better than the current one in which Pogba has shone, while Di Maria was MOTM in the CL final last year and a star of the World Cup) and if all of our midfield eggs are in that basket we are goosed.
This strange clause in the contract suggests that we have been in some form of contact with Delph since January; if so it's a very shrewd bit of business on the part of the club. Common sense, low risk/cost signing that could prove to be the shrewdest of any in the PL this summer.