Radxa is not the same as Raspberry, Raspberry create closed source hardware and provide support for thier hardware via selecting some opensource software channels.
Radxa hardware is opensource and as so can be adopted in any form someone wishes.
It can not get support like raspberry does because it doesnāt go through a closed source release cycle.
It will get support through various communities but being opensource hardware users and sales are actually part of the release cycle and that is fundementally different to the Raspberry approach.
Opensource hardware can bring technology quicker to market and can often be near BoM prices as much as it can be frustrating for users who are expecting a closed source hardware release.
How much support a board gets is all about the impetus and popularity around it and the communities it forms.
It could garner Raspberry like software support equally as it may fail as gauging impetus and popularity is very like guaging the length of a ball of string.
Its definately a very interesting board that takes what we have had as a SBC to a whole new level, but how adoption and popularity goes, who knows?