Yeah, I've wondered that too - seems pretty reasonable, really. But I haven't seen the theory borne out, so far. Well, not much - some folks, yes; most, no.
Actually, it's been a couple of the 'rules-liter' games where I've seen the most attachment to PCs, and in particular strong feelings about the dying of said PCs. Making characters up, and statting them out, hasn't - typically - been the biggest downer.
For me it comes in when I have developed a personality for my character, "gotten into it" if you will. That is when it bugs me. However, I accept it because I like death being real.
Why is there raise dead, etc...? Because coming back to life is a pretty common "story" in many histories, especially when they are also a hero. It is also a great way to allow favored characters to continue to be played.
When PC's die in my game it is up to the player if they come back to life, or start a new character. Usually they like their character and want to continue with it. So they are raised/resurrected.
I also do not penalize characters, or players, for the PC death. I do not make them play a character one level lower, I do not make them lose a point of CON, etc... The death itself usually creates more then enough angst, I certainly do not need to add to it with further "punishments".
I also hate it when DM's do add the insult to injury, because it "Makes it more realistic". Coming back to life is realistic?
I also do not agree with lowering the PC level for new characters. I award XP's to the player, not the PC. The player is the one who has put in the time and effort to earn those XP's. To make them play a new character of a lower level devalues the contribution of the player, and punishes them for their PC's death above and beyond the loss of the PC.
I like to run my games as "realistic" as possible, but I also like for them to be fun. So even though I have no problems with there being PC death in a game, I will do whatever I can to minimize the "negativity" of the experience.