The Prius doesn't use Ni-Cd batteries, it uses Ni-MH (Nickel metal-hydride). The battery packs are long-lasting and completely recyclable.
Which vehicle do you currently drive that delivers 65 mpg? The only thing I can think of is an Elio 3-wheeler, or maybe a carefully-driven Geo Metro 3-cyl. If you really are able to achieve this figure, and like what you drive, you may just want to stick with your current car. Even a Smart car can't get anywhere close to that.
Fuel economy is not the only strength of the Toyota Prius. Its low emissions are a significant perk. It also has a unique, smooth and quiet driving experience, class-leading features, cargo versatility and low ownership cost.
It's not for everyone, though. No one's telling you to buy one.