Uv has nothing to do with anaconda becoming unnecessary. That's something that's naturally happened ecosystem-wide, over a period of years, due to build systems improving and developers publishing a broader range of pre-built wheels. There are still gaps in the system, because the standards-defined system of metadata can't capture all of everyone's needs (see https://pypackaging-native.github.io/ for an overview).
Poetry was arguably "necessary" in 2018, but pip's dependency resolver fundamentally changed in 2020.
The "vanilla" Python packaging toolchain has been gradually improving the whole time and people haven't given it much credit for that (largely because pip is still bad, and partly because they still resent that Setuptools is no longer interested in trying to be an all-in-one solution). Uv is largely possible (rather, as good as it is) because of that work (and because of the cooperation of uv project leadership with PyPA).
Poetry was arguably "necessary" in 2018, but pip's dependency resolver fundamentally changed in 2020.
The "vanilla" Python packaging toolchain has been gradually improving the whole time and people haven't given it much credit for that (largely because pip is still bad, and partly because they still resent that Setuptools is no longer interested in trying to be an all-in-one solution). Uv is largely possible (rather, as good as it is) because of that work (and because of the cooperation of uv project leadership with PyPA).