Torch the Franchise and Run: Kieron Gillen, the creator of my young self's very well regarded run on Journey into Mystery gave this as the reason why, and here come the spoilers mortals so avoid highlighting or clicking any following links to avoid being sullied, my younger self had to not only die, but be absolutely removed from existence. He was well aware letting him survive, or even "simply" die, would have provided someone with the opportunity in the future to do an ill-conceived "let's have him turn evil and completely undercut the importance of his earlier stories" plot. Even this, he admits, will not necessarily keep later writers from finding some way to bring my younger self back into existence. He kindly advises, though, that they not do this, as even if they care about the character, it will only allow even later writers the same vicious opportunity. A scheme of both subversion and cruelty after my own heart. Though I suppose it's more like my scheme was after his, this time.
Myself, rather miserably I might add: The House always wins.