The user can. BinaryIdiot means striking a deal with a manufacturer, the same way PC manufacturers make agreements to preinstall software on Windows machines.
But while manufacturers such as Samsung can and have agreed to preload Microsoft apps on Android devices, I don't think Google would allow manufacturers to change the search provider. Though that still doesn't prevent them from preinstalling Cortana, or replacing the homescreen with a Cortana launcher.
Partnering with a custom ROM such as CyanogenMod is certainly an option, too.
I assumed Google's requirements for allowing the Play Store on devices would include making Google the default search engine, but I may be mistaken, since it seems Android devices with Bing or Yahoo as the default have appeared in the past.
I'm sure Google would love to add that requirement. But with antitrust regulators from the U.S. and EU salivating at the chance to hit them for monopolistic practices they will avoid anything as overt as that.
Then why does Microsoft say this in their blog post:
>Although the functionality will be very helpful, because it’s “just an app” there will be certain things that Cortana does on Windows phones that won’t work on Android devices or iPhones. Some features require access to the system that aren’t currently possible with iOS or Android, so things like toggling settings or opening apps won’t initially be available in the Cortana companions for those platforms. Similarly, the ability to invoke Cortana hands-free by saying “Hey Cortana” requires special integration with the device’s microphone, so that feature will be limited to Windows Phones and PCs.
Is it a design decision or a platform restriction?
Tasker can certainly change settings and launch apps, so I don't see why Cortana couldn't. Maybe Microsoft just means it's more difficult? They do say certain features "won't initially be available", which implies they will in the future, though this contradicts the statement that the features "won't work".
Hands-free voice control is tricky because Qualcomm controls hardware support. There are some workarounds if you don't want to license Qualcomm's tech, but I guess Microsoft may not want to use such hacks. Otherwise, without Qualcomm's dedicated always-on voice coprocessor, leaving the mic on would drain the battery.
But while manufacturers such as Samsung can and have agreed to preload Microsoft apps on Android devices, I don't think Google would allow manufacturers to change the search provider. Though that still doesn't prevent them from preinstalling Cortana, or replacing the homescreen with a Cortana launcher.
Partnering with a custom ROM such as CyanogenMod is certainly an option, too.