You are exaggerating quite a lot. Many of the core AA lines for every class starts pre-underfoot. Also consider the fact that many AA lines have deminishing returns the further up you go on them. While not an optimal investment scheme they will be far from useless. A person starting with all AA through underfoot vs someone start from zero would be dramatically in favor of the person with those AAs and WILL have a very definite effect on their individual power and performance, More than enough for them to be able to fill in the gaps afterward. Also the number count would be closer to 5000 AAs maybe more.