First, I don't think your specific point is true. Second, and more importantly, the benefit of hardware isn't that it changes the constant factors; it's that it parallelizes the search. The whole point of scrypt is to create a state explosion that prevents that parallelization.
Parallelization is a constant factor. If you have 1000 processors, you get a constant-factor one-time speedup of 1000x (or less). No complexity class changes.
Comments
First, I don't think your specific point is true. Second, and more importantly, the benefit of hardware isn't that it changes the constant factors; it's that it parallelizes the search. The whole point of scrypt is to create a state explosion that prevents that parallelization.
Parallelization is a constant factor. If you have 1000 processors, you get a constant-factor one-time speedup of 1000x (or less). No complexity class changes.