That being said, as someone who has been making memes for 6+ years I can tell you hands down no mobile app will ever compare to the power of photoshop, or GIMP for that matter. Even if it was possible for a mobile app to do everything photoshop can do, the small screen size and touch screen interface is a huge issue that can't be solved without plugging a mouse + keyboard into a tablet, at which point, just use a computer.
There is an interesting phenomenon that the younger generation is so enamored with mobile apps and devices that many of them don't realize how certain use cases/work flows simply are always going to be way better on a desktop or a laptop. I would characterize your comment as saying its possible to profit off of the ignorance of a certain subset of today's 15-25 year old's when it comes to this fact.
I know there are so many brilliant people in this generation who are going to be sick nerds one day. But lots of others only interact with computers via their phones and don't even realize how silly they are being by refusing to make memes on a laptop.
This made me smile
So, to all the folks here saying GIMP or MSPaint and call it a day ... you are missing the boat. The modern-day instagram/twitter memes are an entirely new vector of communication. The bar is getting lower, it will get lower, and there is a way to capitalize on this.
One day soon an app will exist that will allow you to make memes the same way instagram allows you to tap one finger and make a photo look like it was taken on a polaroid camera. If you do it right to where you can produce content like heckoffsupreme, sonny5ideup, tanksinatra, middleclassfancy, gayvapeshark, etc... with a few taps and some original verbage you'd make a killing.
Also super glad to see heckoffsupreme get an honorable mention. They are some of the best, no doubt.