Non of those were taller than 1.85, usually it is those who are 1.9+ that lasts longer. De gea is taller than Buffon so the chances are there.
And btw, while I was writing my post I was thinking to write something about I won't mind getting either of them over MATS, but then I realized they most likely end up in RM or PSG -if they moved- which is a scary thought IMO.
I guess there might be a correlation between heigh and sustained success. I think Kahn had a steep decline once he hit 33/34 too and he was about as tall as ter Stegen.
I would not have Courtois over ter Stegen. His footwork is pathetic and he's been on a downward trend for some time now. It could be related to him absolutely hating to be in Chelsea and England, but not worth the risk.
DDG however is another case. It really depends on how MAtS develops though in the next couple of years. If he manages to take some big steps forward then I would stay with him. If he's still at the level he is today and not improving, then it would be enticing.
Not that big of an age difference. 1990 v 1992.