for 150 packs, it's about a 1 in 10 chance of getting 6 or fewer legendaries. Sure that's very below average, but it is not a super rare probability. (It is also approximately 1 in 10 of getting 12 or more legendaries, so if you know anyone like that, they had something equally unlikely happen).
So yeah, 6 is unlucky, but play hearthstone long enough and you will see things 100x more unluckier happen.
Hello everyone!!, I am Chroxar, a player from Argentina. I wanted to tell you that out of 94 packages, 80 + 5 of the pre-purchase plus the first ones of the battle pass. I got the 2 golden legendary gifts and another 12 legendary (2 golden) Then I opened another 85 packages with gold and got 4 more legendary