Legal existence is the be all and end all of political parties. Candidates beseech the permission of the party to run under its name.
The RNC is separately incorporated and is not "THE PARTY" however it has an annual and semi-annual meeting responsibility AND it administers the presidential nominating convention.
It is a simple matter to create an alternative body and have the states sign up to use it for those purposes ~ and there are undoubtedly some state Republican parties ready to do that. I used Texas as an example ~
Back before the Civil War there was quite a bit of party organization agitation. The Whig party fell apart. The Republican party rose up ~ but the Democrat party also fell apart and broke into Southern and Northern branches, and two other parties coalesced around independent candidacies which were also positioned to deal with the slavery question.
At the state level these various changes were a zoo but that's where the real action was, particularly for the Democrats who ended up in two separate countries in roughly the same states they started out with, but without a working coalition.
Then there was the war, the war ended, things were stuck back together, new ways of coordinating the state parties were worked out and finally that all came to an end with the compromise of 1876.
I don't think anything happened during that period when it comes to party organization that couldn't be done over with the modern Republican party machinery.
It's time to try it ~ we have a problem and those people need to be cut loose ~ after all, where they gonna' go, to the Democrats? BWahahahahaaaaa!!
Tell me again where the members of the RNC come from and are selected?