Grass is not dead whatsoever. You were correct that Tapu Bulu is a competitive grass deck, but have you forgotten all about Golisopod-GX! Golisopod is a great deck that rivals Bulu in many ways, especially since it had such a great showing at worlds with Garbodor. Having 2 competitive decks in the meta is plenty for any type, grass included. I wouldn't even begin to mention any of the other decks because they pale in comparison to Bulu/Golisopod, and won't be anything more than outliers this season. All in all grass decks are definitely not dead, and I wouldn't be suprised to see them have a great showing this year.With the exception of Tapu Bulu GX and (maybe) Lurantis GX, yes. Decidueye/Ninetales is still playable but it takes a massive hit from losing Forest. Bulu is very much alive but will never be as good as Decidueye variants were. Lurantis is still playable but is a little bit underpowered. However, we have the new Shining Genesect and Venusaur coming in Shining Legends and I think they could breathe some life back into the Grass type.
Good god, I managed to forget Golisopod xDGrass is not dead whatsoever. You were correct that Tapu Bulu is a competitive grass deck, but have you forgotten all about Golisopod-GX! Golisopod is a great deck that rivals Bulu in many ways, especially since it had such a great showing at worlds with Garbodor. Having 2 competitive decks in the meta is plenty for any type, grass included. I wouldn't even begin to mention any of the other decks because they pale in comparison to Bulu/Golisopod, and won't be anything more than outliers this season. All in all grass decks are definitely not dead, and I wouldn't be suprised to see them have a great showing this year.