In my opinion they are not. I don't know where this "Live tiles are dying" hysteria is coming from. I am sure live tiles will be added to the new built in apps. They are not feature complete right now.
The tiles aren't going anywhere. While I agree that Microsoft is getting rid of most of what made Windows Phone unique removing tiles would just make it too similar to android and iOS. Also Microsoft is showing us that tiles are here to stay why else would they keep them in Windows 10s start menu?Hubs = gone
Panoramic apps = gone
Pivots = gone
Stylish typography = gone
One handed use = compromised
What makes Live Tiles so invulnerable than the rest that made WP so unique? According to that ex-MS clown and some of the "writers" on this site the design language is what held back WP from mass acceptance. If that's the case then you just know that MS is on the way of removing or toning down the Live Tiles. They already put in a transparency slider to dial them down next to nothing.