> the way `python -m pip` searches for the module to execute is much 
> closer to the way Windows searches for a command like `pip` (i.e. 
> current directory first)

That's classic Windows behavior. However, search paths for CreateProcess and the loader are composed on demand, which allows different behavior to be selected easily enough. The current behavior depends on a mix of environment variables, registry settings, reserved names (known DLLs, API sets), application and DLL manifests, .local redirection, and in-process configuration. For example, to skip the working directory when searching for DLLs, there's the CWDIllegalInDllSearch registry setting, SetDllDirectoryW(L""), or SetDefaultDllDirectories (the latter removes PATH as well, so it's not suited for loosely-couple systems). To skip  the working directory when searching for executables, define the environment variable "NoDefaultCurrentDirectoryInExePath".