Agreed that it's moving down the value chain, many other open source projects out there doing similar things. There's also Tyk Open Source API Gateway (https://tyk.io) and API Umbrella (http://apiumbrella.io/), and APIAxle, though that's been around for a while now.
Is small from a VC prospective. Especially in 2015-2020. Everything under 1B is tiny. Plus, when there are soo many players you will end up fighting like crazy just the get bread crumbs.