IMO, apps don't stand a chance unless you can create an addictive game like clash of clans or a super interesting app like Prisma.
Even Prisma isn't going to make a huge impact in the long run.
When I saw pictures modified using Prisma, I was waiting for it. Installed it the day it launched on Android. Once the initial curiosity died down, I haven't opened it. I doubt I'll open it again unless they introduce something drastically new. Slowly, it'll get uninstalled and forgotten.
Especially true once they figure out ways to monetize their offering. Since they use cloud to process the file and not the phone, their expenses must be pretty high. The free offering has some attractiveness. But why would I pay money for such an app? Maybe I'll pay for an app that can get rid of noise and shakes from every photo I take. But not something like Prisma which distorts the picture completely.
Apps need active users. How many apps would we need that we'll use on a daily, or even monthly basis? Unless as you mentioned, apps can create new categories (like what Amazon US did with online shopping), it's not going to find a place in our phone.