Bad example. Choke lever was a control device that became unnecessary as technology made the relevant part of the process fully automatic, and it was completely incidental to the overall purpose of a car - to move people places.
Messing with URL and search is like messing with the steering wheel, or - in case of self-driving cars - with navigation input.
This is only true if you assume that differentiating between a url and a search query. In a sense, a url (or uri) is just a specific type of query.
We could equivalently ask why ftp and http and https and such don't have different types of entry uis, since they're different protocols. If we consider the "resource location via plain language" protocol (which we could even formalize!) that defers to http(s), ftp, Tor, and Bing based on aspects of the request, it's just one higher level protocol.
Messing with URL and search is like messing with the steering wheel, or - in case of self-driving cars - with navigation input.