I think it is more the other way around: feature parity to aid switching to rather than to reduce loss of shre due to people switching from.
Those of us using Android who care that much about the privacy aspect have ways to implement it (a little more Heath Robinson like, but still...) using a VPN and alternative browsers. Many in the Andoid camp are likely to see this are preferable to switching platforms and paying more for their devices (unless they run with expansive flagship android units in which case cost is less of an issue in the switch). Those that don't care that much, don't care enough to make a difference.
On the other hand Apple providing extra privacy protection is a significant extra bit of friction that would stop people moving away from iDevices onto Android ones, even amongst people who don't care enough to make any effort beyond not switching and/or don't really understand the issue much if at all.
Those of us using Android who care that much about the privacy aspect have ways to implement it (a little more Heath Robinson like, but still...) using a VPN and alternative browsers. Many in the Andoid camp are likely to see this are preferable to switching platforms and paying more for their devices (unless they run with expansive flagship android units in which case cost is less of an issue in the switch). Those that don't care that much, don't care enough to make a difference.
On the other hand Apple providing extra privacy protection is a significant extra bit of friction that would stop people moving away from iDevices onto Android ones, even amongst people who don't care enough to make any effort beyond not switching and/or don't really understand the issue much if at all.