To try to prevent the continual disruption to teams from predators. Nowadays we have agents stirring the pot intent always on moving players to gain a fee. There is also the 'stockpiling' of players by teams like Chelsea & City. This is also a much bigger and richer market than the 60's when we were the top dogs predating on amongst others Chelsea. Like all markets control is needed otherwise the big fish just swallow all the little fish. Ending up with one big fish is no good to anybody including the big fish. Playing with themselves is not the most fun you can have with a football. But you know all this I'm sure PS!
Perhaps there may also have been unintended consequences because the bigger clubs used to have much smaller advantages.
tbh you have to take Martinez' and Pulis' comments with a pinch of salt; as while whining about being unsettled by big clubs during the season, both have openly admitted that they would like to bring in 2-3 players before the window closes. So make up your mind - you can't have your cake and eat it! I think that one of the reasons a late window is currently so essential is the sheer lunacy of most PL clubs' post and pre-season tours. It must be incredibly hard for managers to truly get to know their teams and focus enough attention on new incomings/outgoings when every other week you're making a long-haul flight to never-never land to raise some money for the tuck shop back at Hotspur Way. Back in a routine with regular training and a chance to sit down in the office with his coaching staff and really study the squad at his disposal, I'm sure the average manager is grateful for the extra few weeks to get deals over the line. If a pre-season was simply a short trip to a nearby country followed by a series of friendlies at WHL, I'd be all for closing the window when it logically should be closed. Maybe Arsenal would even let us compete in the hallowed Emirates Cup