That all depends on how many pages a person "likes" and how often those Pages post content. According to StatisticBrain.com, as of July 2014, the average FB user likes 80 pages. That could bring quite a more posts into an average person's newsfeed. However, we also tend to "like" pages on a whim or never unlike pages we are no longer interested in because it doesn't affect our newsfeed. If people started seeing all the posts from the pages they liked, I think they would just be more judicious about what pages they choose to like (or remain liked) and which they choose to see the content from.

Would people be missing some posts? Possibly, but from what I've seen FB users are more apt to scroll back through posts than Twitter users go back through older tweets. So, I also think it's possible that most posts would be seen. Some organizations may see the number of "likes" go down initially as people who weren't really interested in the organization's posts unlike them; however, the number of likes would more accurately reflect the number of people who are really interested in the organization's posts.

One of the things I wonder about, though, is if 75% of businesses/organizations were paying to have their updates shown to all their followers, that would put a lot more content into people's feeds. Most people probably wouldn't see everything in their feed. So, would businesses be happy paying $10/mo only to find out most people still aren't seeing their updates? It probably depends on the numbers.