I've done a search on the history of adhoc wifi support in Android and there's a consistent pattern of ignoring this and then going "won't fix, obsolete" after waiting long enough for it to effectively age-out of the issues tracking system.

Therefore, since I'm unable to comment or vote on any active tickets regarding the featrure request for an Ad Hoc network support I'm adding a ticket to your system.

The original is quoted below but I think there's more that needs to be considered given current developments in the networking community.

There are a number of active projects to create an ad hoc networking solution, aka mesh network, using cell phones to extend the current networks, provide networks in communities where none exists either because of technology or disaster which have been trying to develop work arounds for this and they all are essentially rooting or replacing the core functionality of the networking components.

Examples of this include such projects as:
Serval Mesh (http://www.servalproject.org/)
Open Garden (https://www.opengarden.com/)
Right Mesh (https://www.rightmesh.io/)
Apple Iphone (iOS 7 and above supports this)
Haiti rescue operations in 2010 (https://www.technologyreview.com/s/516571/build-your-own-internet-with-mobile-mesh-networking/)
Additional rescue operations that benefited from ad-hoc networking operations include Hurricanes Harvey, Irma, Maria.

Finally there is growing support for this type of functionality on a global scale if you can consider the UN resolution (http://techland.time.com/2011/06/07/united-nations-report-declares-internet-access-a-human-right/) that connectivity may be a human right and that no government should be able to shut down that communication.

In short - the need for ad-hoc mesh networking for smart phones is here and arguably even overdue.

While these solutions utilize a combination of Bluetooth - WiFi - Cellular data to build out the networks, the fundamental problem is that establishing AdHoc WiFi networks that can be efficient, secure (VPN and/or WPA2), and consistently implemented is lacking. Security is a must and cannot be blocked but could be enabled as part of the implementation.

In order for these fragmented communication platforms to work effectively some core functionalities need to be developed with the eventual requirement that it become cross platform capable, providing other platforms are willing to use a non-proprietary interface.

The ability to support wifi ad hoc networking will allow use cases
currently not supported by any non-wifi phone and even on the iPhone ad hoc
networks are not officially supported. This could be a significant
differentiator.

The use cases I have in mind include using wifi to message friends on a
plane or bus where you couldn't get a seat next to each other.