I’m willing to bet that there are projects at every chip company looking into how to drive down these costs. The first step is to put the architecture of the model and the backprop into silicon. The weights are the only variables so if you can reduce those to cheap and fast modules that can be mass produced you could come up with something cheaper than a GPU. If the profitability of running and training this specific model is high enough than its worth the investment of time and money to set up the production line.