The point is, with 3 weeks of gearing, you and your friends could clear normal, maybe heroic tomb, with 1-2 legendaries, bis dps or otherwise.
You can get to artifact level 60+ in a week, assuming you hit 110 right after reset with a fresh toon.
Legendaries and the rate at which you acquire them aren't the things that are holding people back. Even with 1 leggo so far, that would be 2 (because crafted ones exist) and 2 legendaries as statsticks coupled with 900+ gear is more than enough to raid tomb at anything sub mythic.
And despite all of the cries of "oh its a bad design" in previous expansions you'd have a grand total of
0 legendaries in the same time. Zip. Zilch. Nada.
You'd be farming Mogushan vaults for quest drops though
Doing Highmaul for Aberjabbers
Joining ICC pugs to see "shards on res"... hell you wouldn't even have the base axe crafted by then.