The tax credit difference is about over, and that advantage will be gone. The point is that Ford has to price the Mach E's MSRP at least as high as the Model Y to make a profit. Their margin will still be a lot less than Tesla's almost 30% for automobile manufacturing. The tax credits don't go to either company's coffers as they would sell every car they can build anyway.
No one should be critical of the increases as Ford's E business must profit for the company to survive.