To this day, it is odd to me that Fox let a franchise die that brought in a lot of revenue with an extensive selection of merchandise in the late 90s/early 00s. Even without Joss's direct involvement, they could have easily done a spin-off with a writer from the original series and Joss's blessing, but they chose not to do it; and now, while the Buffyverse still has its loyal following, it is not on the same scale as Friends or Gilmore Girls, franchises that has been kept alive by an overwhelming growth in younger fans (not to say Buffy does not gain younger fans now, but definitely not on the same level as the other two shows).
One executive at FOX said that they definitely want to reboot Buffy; and the industry enjoys rebooting (Charmed, Prison Break, 24, Roswell) - it is surprising that they have not done so already. In a way, I like that it has not happened yet, because it seems to me like they really want to get it right and not create a Charmed situation where they antagonise an entire fan base.
I think the reason why we have not heard about the planned reboot anymore was FOX's merger with Disney; that probably put things on the back burner, but I think the time will come where Buffy is rebooted or revived in some form, I just hope it will do the original show justice and also be able to stand on its own.