Three problems I can think of
1) Why should someone who doesn't watch the BBC be forced to pay through their internet connection charge?
2) Why should only the BBC be subsidised to provide a streaming service*?
3) Will this only apply to domestic / consumer connections, or is that connection to a road-side data collection node also going to "contribute"?
* Especially when the other providers provide better content outside of news, current affairs and the like.