Poetry is a tool to install packages, in whatever form they're in. It's roughly in the same space as pip/easy_install or virtualenvwrapper, but it's really a higher-level tool than anything that is currently standard, which is what makes it worthwhile. (It's in the same space as Cargo, if that helps.)

Wheels and eggs are packaging formats, which Poetry (and pip) installs. You can think of poetry as like yum/dnf or apt and wheels/eggs as like .rpm or .deb files. (You can think of pip as like the rpm or dpkg command, in the sense that it's a lower-level tool but it also installs wheels/eggs, but that analogy isn't perfect.) The existence of Poetry does not obsolete either wheels or eggs.

Neither wheels nor eggs replaced setup.py files - the standard way of building a wheel is to run "setup.py bdist_wheel". You can think of setup.py as like Makefile. You would not say that tarballs have replaced Makefiles.

The final output of Poetry is a wheel so it's not an egg/sdist/wheel competitor.

If you're familiar with Ruby, a good mapping would be: gem (file format) is like wheel, gem (the command) is like pip, and bundler is like poetry. It just manages / ties everything together.