[kllrnohj]

You made a broad, vague claim that iterator guarantees were broken. You misrepresented it as being a much larger issue that it actually is. Nearly all iterator guarantees are not broken. One very specific guarantee in one very specific case is, that's it. And it's a rare, not general, case at that, making the trade-off necessary to achieve it a bad default.

[gpderetta]

returning, moving, swapping a small vector would break any pointer to an element. That's a big deal. Interior pointers are used all the time (that's, more than performance, the primary reason that reserve exist).