Why does the Hyper Accelerated Dragon avoid the Rossolimo? After
1. e4 c5 2. Nf3 g6 3. d4 cxd4 4. Nxd4 Nc6

Why is the Rossolimo line impossible for white?

[fen ""]
1. e4 c5 2. Nf3 g6 3. d4 cxd4 4. Nxd4 Nc6
In the Rossolimo proper,

[FEN ""]
[Title "Rossolimo variation"]
[Startply "5"]

1. e4 c5 2. Nf3 Nc6 3. Bb5 g6


white usually holds back pawn to d4 and doubles black pawns with Bxc6, or later builds a center with an eventual c3 followed by d4.

In the Open Sicilian,

[FEN ""]
[Title "Open Sicilian"]
[Startply "9"]

1. e4 c5 2. Nf3 g6 3. d4 cxd4 4. Nxd4 Nc6 5. Bb5?!


none of these plans are available, and 5. Bb5 doesn't make much sense. Besides, the bishop on b5 is tactically vulnerable to a later black Qa5+ or Qb6.