Fallout 76 has been a complete a disaster. I don't think Fallout is dead yet, I think Bethesda can still turn things around. But the next Fallout game has to go back to being a single player RPG, and it has to be a damn good one at that.
Personally I loved Fallout 4 (despite it's flaws) but the fanbase in general seemed to be more indifferent to it, and 76 has been pretty much a complete disaster entirely. If the next Fallout game has another bad showing then I don't see a bright future for the series.
However before trying to rebuild Fallout's reputation, Bethesda has to rebuild their own reputation. Lets hope Elder Scowls 6 and Starfield turn out out to be good games. If Bethesda can put out a couple good showings and patch Fallout 76 into a workable state, then they may be able to wash away this negativity they are in right now.