Huey, I don't think it was ever thought that the AWTs would increase wagering revenue. As far as I can see, the objective was twofold. Firstly, to provide an excellent year round training facility in each region and secondly to take the pressure off the diminishing number of grass tracks over winter. They seem to be doing that.
As Freda says, they are unlikely to significantly increase or decrease wagering revenue overall. Mostly done with free money to the industry, I don't really see the problem. Like any surface, heavy or firm grass or AWT, they will suit some horses more than others and even that will likely vary given that the moisture content clearly affects the speed of the surface quite significantly. From a punting perspective, I don't really see much difference. I've certainly done a lot better on AWTs over the last year than on grass but the n for that assessment is limited.