No matter what method you select for generating your online income, there's one very important thing to understand. Today, across this globe, with its 7+ billion inhabitants, there are two recurring things that people are looking for more of. Either people want more time or they want more money. The truth? Time is far more valuable than money. You can't recreate time. Once it's spent, it's gone forever. Not money.
Now as to your comment on traffic it is true, traffic is important. But the truth is, acquiring traffic is easier than converting it. Plus we have many posts dedicated to traffic generation on this blog. Simply check this post, this post or this post. But must importantly, the reason why people struggle with traffic is that they try to promote a sales page or a heavily biased piece of content. Nobody wants to share that, nobody wants to link to that, and as a result you don't get traffic and blame your lack of success on traffic (like you did in your comment above).
If you have pop-ups and optins on every page, I would have to think that it would be a lot harder to convince someone to link to it. Especially since the pages where you have your optins (and probably receive the most traffic) are probably the same pages that you have your best content on as well that you'd be hoping to pitch in your outreach campaign.