What about OneD&D makes it more capable of reaching "further masses" than the existing game? What is the "unifying" force your envision?
In any case I own most of the 5e books and intend to keep playing it or derivations of it indefinitely, but I'm not sure I'll even get a PHB for OneD&D, a project that just holds no appeal for me. I'd say I've been divided from the OneD&D fans. I'll accept that I might be a weird outlier, but it still emphasizes the point that I just don't see how this OneD&D project brings more unity by driving away the 5e grognards to create a mostly identical product with presumably the same general level of appeal.
I do think it's possible that, with the SRD going creative commons and WotC putting out a pointless clone as their new edition, one that practically challenges everyone with a game design itch to do their own version, that a galaxy of broadly compatible 5e clones will take up a lot of the ttrpg space. So if unity means more people playing things loosely compatible with 5e and OneD&D, sure that seems plausible enough.