Why don't top GM's play the grand prix attack?

Many club players use the grand prix attack against the Sicilian, sometimes with Bc4 and sometimes with g3 and Bg2. It seems easy to play for white, simple plan of Qe1-h4, Ng5, and f5, and not so easy to defend with black. It also seems sound from a computer's prospective. I don't play the grand prix attack myself but it looks like a good option vs. the Sicilian. My question is why don't more top GM's play it? I mean, if it's so great, why aren't people like Nepo and Big Shak playing it?

They are theoretical artists, not Grand Prix barbarians 

Also they probably know how to refute it

I could reverse the question. Why don't most of amateur players play open sicilian?

Polgar used to play it.

Because it’s not that hard to beat off white primitive style attack

white's options are rather limited. there's f5 and bh6 ng5. there's e5. there's a3-b4 gambits. at present only the f5 lines survive as far as i know. and by survive i mean white is equal at best, with an overextended pawn structure to deal with. with the open sicilian white has much more to fight with. different plans. black has to know more.

i mean....she still played those games lol. Perez and Topalov are both world class players

Gawain Jones who is rated 2600+ plays it.

cuz it sucks

cuz they like bb5 and agree on a draw -_-

It’s too one sided: since whites so committed to his one plan lack has a pretty easy path to equality, especially with computers that can analyze the double edged positions out.