If it was not a money grab by ISP's they would offer the users who only use their connection for things like checking their email once a day better rates as they barely use any bandwidth at all.
There seems to be an association with someone who uses a lot of bandwidth as being a pirate. The fact is that more and more people are streaming video/music from places like YouTube and news/sports sites everyday. This adds up, especially with the HD streaming kick thats going on currently.
Also, if you ISP's have the need to rate limit customers using certain protocols (ie. bittorrent) which is pretty popular these days, it is likely only a small percentage who are really using the biggest portion of your bandwidth overall. So why punish everyone when only some people are offending? And what about the legitimate uses of bittorrent (or whatever protocol you decide to limit) ?
There is value in having DPI in your network to use it to educate and partner with websites that your customers are hitting to better their experience, its just sad that the people making the decisions are blinded by dollar signs or to nontechnical to realize this.