The PyPI website search is implemented using a real search backend (historically Elasticsearch/OpenSearch–style infrastructure) layered behind application logic on Python Package Index. Queries are tokenized, ranked, filtered, logged, and throttled. That works fine for humans interacting through a browser.

The moment you expose that same service to a ubiquitous CLI like pip, the workload changes qualitatively.

PyPI has the /simple endpoint that the CDN can handle.

It’s PyPI philosophy that search happens on the website and pip has aligned to that. Pip doesn’t want to make a web scraper understandably so the function of searching remains disabled