I think those are good estimates given that pool. I'm also thinking of the "unexpectedly popular" effect of the D&D name and adding percentages from another (admittedly imaginary) pool. When Beamdog released the EEs the downloads crashed their servers. And then crashed the backup servers.

Likewise the PoE1 pitch was "the spiritual successor to BG" and the PoE2 pitch was "continuation of PoE. One appeal was wildly popular, the other wasn't.

I do think you would need to ask D&D and not just 5th.