D3 is a completely different game than on release. On release it was all about maxing a few stats (main stat, attack speed, crit chance, crit hit). The differences between one piece of the gear and the next was just a few points. Also gear was almost 100% random drops. This made the AH better, as you could never be expected to find a full set of top tier gear.

Now it's much more based around set bonuses and builds. No more AH, so all gear is self found. But now you have random drops, rift drops, blood shards, cube upgrades, rerolls. So multiple ways to acquire and improve existing gear.