TDMA is an extension of TDM, which goes back to the 60's. Synchronization was already solved. Variable header size could be implemented with the same preamble c

TDMA is an extension of TDM, which goes back to the 60's. Synchronization was already solved. Variable header size could be implemented with the same preamble concept already used by Ethernet, but used to indicate the end of the header. These were not hard problems. The technology existed, the affordability would have largely depended on adoption, so it's hard to say.