Currently, I've been focusing on trying to get my campaigns profitable on pop traffic sources (popcash mostly) with the intention of really trying to learn them well. I was thinking that with the proper tweaking and targeting, I would be able to get really good profits. I've seen a few comments in some older threads though that pop traffic should really just be used to help you get tweak your landers, so that you can then take those well-working landers to some display traffic sources.
That sounds well and good, and I can definitely start doing that but is pop traffic really not something you can bank on? Is it seen as something that can just be used to prep your landers? If so, am should I not be trying so hard to get +100% ROI on my pop campaigns? Is there a certain point where I should stop tweaking and start running some display traffic?
You can absolutely run $x,xxx daily profit on pop traffic, I'm sure there are people here who have gone into $xx,xxx with it.
You'll likely be spread over a few sources when scaling in order to maximize traffic - not all are capable of spending enough to achieve those figures.
Generally spoken: yes.
Will you be able to achieve with just 1 network and 1 geo? Extremely unlikely if it's a source like popcash or popads. You definitely need to scale to other sources, as goldenjo said, preferrably the big managed networks.
If you're worrying that you won't get enough on volume you're probably reached a stage where you're aiming more towards $xx,xxx daily than 4 digits. I wouldn't worry at all at your stage right now, there's more than enough volume available through pops at this stage.
as every one already said YES you can definitely bank only on Pop traffic.
however there are some verticals that are suitable more than other for pop traffic.
the next stage for you is once your campaigns are profitable to add another weapon to your marketing arsenal and that is display traffic,
Make sure to split test once you start from your pop campaigns to your display campaigns and keep the one that generates the highest ROI for you.
looking forward to read more about your activity 
Thanks for the responses all. I just wanted to make sure what I was trying to do was even possible in the first place 
when you are referring to display. Are you referring to display within those pop networks. Example: adcash pop >>>> to adcash display banners? Or are we talking a RTB platform like sitescout?
We do text alert pops and from our experience what works best with it is utilities and mobile content.
Of course we had great success with other verticals as well but these 2 verticals stand out more.
Or its the fact we are running it on our direct pubs.
If you'd like to discuss more about what we do ping me on skype, it will be best.
My Skype is - alon.ezmob