cost的一个用法？

i7123

The main issue today is that the bandwidth necessary to broadcast and store uncompressed digital signals is cost prohibitive。可以帮我解释一下这句话吗,谢谢！

fair_sword

今天主要的问题就是对于broacast 和store uncompressed digital signals 来说是必需的broadcast贵的让人用不起.  

The main issue today is that the GMAT test neccessary to go to study in US and get fee loan is cost prohibitive.