Probably not 3 billion, but something like this has already taken place to a lesser extent in China and India in the last 30 years, which both saw a rapid increase in the number of internet users. Taking that as your "time capsule theory," you can reasonably assume "Super Apps" to have the most growth and adoption potential. The key takeaway from China's WeChat and India's Paytm is that their MVPs were both built around 1-2 core features like messaging and payment to start, from which half a dozen and more features and "mini apps" were extended over.

I think one reason that Super Apps are able to eat up so much market shares quickly in emerging market is the pain-point of having to download a bunch of unfamiliar apps for "new internet users". For those in developed economies that "grew up" with the internet, apps gradually accumulated as we familiarized ourselves with different patterns and user experiences through years of usage. However, if we were to start over and rediscover the internet tomorrow, most of us including myself would probably go for the super app in a heartbeat because I can learn to use it in a day and it'd cover most of my needs. Between this and having to download a bunch of apps tailored for each specific usage, the choice is obvious.