when you compare them to alternatives like nimh/nicd packs of the same voltage/Ah

I have done research and to get a nicd/nimh pack that is simliar to lipo ratings , you will pay just as much for the nicd/nimh or more...if you need 36-48 volts at 10-20 Ah....

of course lead acid is much cheaper, but that is old technology and very heavy , sapce consuming. Still, lipos will continue to come down in price IMHO...making them more and more reasonable in price .