If I understood correctly, you're referring to wrapping an Airnode to serve other protocols. That can even be done on-chain without running any additional nodes. For example, one can implement a custom contract that imitates the Chainlink oracle contract interface, which relays the request to an Airnode (and it can be someone else running that Airnode), and that Airnode would respond back just like there is a Chainlink node behind the oracle contract. This would work if there was an independent free market for third-party oracles, but anyone who has tried running an "unofficial" third-party oracle node knows that you will get exactly 0 requests, so may not end up being very beneficial.

We know for a fact that experience with other solutions help a lot, so shoot me an email at burak@api3.org if you want to work on this or similar stuff.