Very cool project and would be super useful with something like GraphQL, which tends to produce big nested JSON objects. Thanks for sharing it!
One improvement in my eyes would be to remove the "connector" boxes, like `members (2): "Array"` and `powers (3): "Array"` and have the arrow go straight to the array property. Those connector boxes take up a lot of real estate without conveying new information.
The "two big mobile platforms" were not established by an irreversible act of God. Before the current time of two platforms, there was a time of (mostly-)one platform i.e. the Web, and that platform had quite a few nice features.
One of the small conveniences is indeed that you didn't need to develop the same thing twice, which made the barrier to entry much lower. The functionality that you were exposing to users did not need to pass a review at one of two US tech giant companies, which could reject publishing it for any or no sensible reason at all. You were not forced to pay 30% of your revenue to the gatekeepers of the platform. You were not banned to invite users to buy your product in any way that works for them, even if it meant sending you checks over carrier pigeons. There was no _chokepoints_ that a single company could squeeze to further its own interests (after the collapse of IE).