Netflix isn't going to produce a full prime time lineup of shows every year on $8 per subscriber. Not at the costs networks currently pay for production ($1.5-2 million per episode generally... with hit shows up to $10-15 million per episode). Either the ads stay, or they figure out a way to produce shows of the same quality for much less money.
To give some perspective, more than $60 billion is spent on TV advertising per year in just the US. So if everyone were to just sell subscriptions at Netflix's price, in exchange for new television without ads, they would need to get... every person in the United States (including all the babies) to subscribe. Twice, per person. Just to make up for the ad revenue, ignoring all the lost revenue of people dropping cable subscriptions. Otherwise, the money that currently funds producing these shows just won't exist, so there won't be anything for them to sell you.
There is no future with everyone on an ad-free Netflix for new TV with content that costs as much to produce as today's network television.