Brave Browser already has Tor integration in private tabs and working IPFS integration on -dev channel since beginning of this year https://github.com/brave/brave-browser/issues/819
They never promised any Tor integration for the near future, see: https://news.ycombinator.com/item?id=17205441 and the first comment. Brave can do Tor integration because its user bases is much smaller than Mozilla's (scaling the Tor network to support the load from all FF users still requires much work).
https://github.com/mozilla/libdweb is one of the efforts, and it provides experimental APIs needed in Firefox to have a nice experience. So AFAIK, Mozilla not only talks about dweb, but also helps with the effort.