The in-development Neo900 smartphone, whilst it doesn't have the latest and greatest hardware specs, is specifically being built to make it harder to do this crap. Option of going 100% FOSS on the main ARM processor with the exception of some userspace blobs for the PowerVR GPU (at least that is the intention) plus a hardware architecture that prevents the closed parts of the system (WiFi, cellular radio etc) from having access to the other hardware (there is no way to for the cellular module to have any access to the microphone, speakers or the memory or flash/filesystem of the main processor at all)
No walled garden (since its 100% FOSS there is no control by anyone other than the user), not trying to sell you apps (no app store means no apps to sell) and no spying or tracking (unless you happen to install something that does spying or tracking)
Is the Neo900 for everyone? No. But if you want a phone that genuinely gives YOU the user the control, the Neo900 is the only device out there that can really do it... (and although not everyone likes binary blobs, the nature of the Neo900 means that if someone does produce a FOSS driver for the PowerVR stuff, it can be use on the Neo900 no problems)