Real landlines are a rarity these days, most stuff is VoIP. In any case, I was talking about getting an emergency call to the person wearing a pager (as in the case of doctors or other on call people), not the reliability of calling 911/999/112/whatever. Any mobile device is going to be more useful than a landline in that situation because the doctor could easily be out at the shops or having lunch. Pagers were invented for that particular scenario.
This probably varies wildly but in the US (or parts there of) landlines have to work in emergency situations - ie no power. Even if you have a 'phone line' delivered over optical the phone company provides you with an optical network interface device with a battery backup. I keep a landline just for emergency scenarios (also 911 actually knowing where you go if you call them and can't relay your address). Can't get that with no account virtual VOIP services or even rely on the big mobile providers to give you that functionality.
