Is it true
 

Things to know:
- Dura-Ace et al are released on a roughly 4 year cycle with a new Ultegra groupset coming out the year after. (Right now, Sora is on the same year cycle as Dura-Ace)
- We are already past the new Ultegra release, so it is likely that if you want a different new Ultegra than the current new Ultegra, you'll have to wait until 2021.
- Per Shimano, the function of R8000 is virtually the same as R9100. The differences thus lie in the materials and aesthetics which drive cost (~2x) and weight (300 grams).

At this point, even Tiagra has quite a few of the elements of the previous generation of Dura-Ace, and the new 105 (R7000) has even more.