While issuing an apology about something he said in Canada this week, Netflix CEO Reed Hastings casually mentioned that the company is "looking at adding a streaming-only option for the USA over the coming months."
Having more subscription offers and price plans is probably better in the long run. Personally, I use the Watch Instantly service much more than I used to considering how much more content, especially from TV, are available now.
But there are still many, many more titles that are only available by mail, so I'd rather have the option of both. But if the streaming-only option is priced lower, then it would be great for anyone on a very tight budget.