Alex is definately hittable and he's also getting old so yeah I don't think an Ank finish is impossible at all even if I think its less likely.
I think a few factors have become together here for so many to think that Anks grappling is the the major factor here....
1.MMA fans tend to get stuck repeating a certain arguement, Alex being vunerable to grappling was heavily pushed when he was very green to MMA, he's not green anymore but people cling to it.
2.Ank is a Dagistani and so its viewed that grappling is his main strenght.
3.Alex is strongly disliked by Izzys fanbase and the idea he's ducking someone who could easily beat him appeals to them.
I mean I wouldnt rule out grappling being a factor but the idea Ank can just push to the cage, get easy takedown and finish? not born out by what we've seen from either man IMHO.