For one, I think competition, there is Kenneth Reitz' pipenv and then of course conda's environment.yml. I think pipenv lost the popularity contest but somehow lead to a situation where people wondered on which horse to bet.
Conda also takes a lot of market share esp. in the machine-learning deployments while also being not a 'perfect' tool.
Pretty sure we will see more poetry in the coming years.
Last but not least Poetry sometimes also feels like a weird tool. For example, when its dumping colourful stack traces on you in case of (invalid) inputs, etc.
If pip-compile would support dev and production requirements it would still be my way to go I think.