I think that dismissing automation out of hand is short-sighted. Over the life of a rapid transit system savings in labour costs must massively outweigh the incremental increase to capital costs. Plus, it delivers a higher level of service to passengers: greater frequency through shorter train headways, the ability to maintain greater frequencies during off-peak hours, and the ability to fine-tune level of service to infrequent and unpredictable events, such as the end-time for a major sporting event or public celebration.
With respect to elevated vs tunneled vs at-grade. They all have their role. The Millennium Line utilizes all three, albeit overwhelmingly in an elevated condition. Lougheed Highway is a wide regional highway masquerading in places as a local arterial. Placing the Millennium line within this corridor meant that property acquisition costs were minimal, construction disruption was minimal (since there was sufficient road cross section to build the line without closing street access, less a lane in each direction), and, most importantly, it is fully grade separated. I don't pretend that the elevated guideway is ideal or intrinsically appealing, but it's not uniformly awful by any stretch of the imagination.
There are a variety of ways to use elevated along (or alongside) street streets without destroying them. Here are a few examples:
Quebec Street (City of Vancouver):
https://goo.gl/maps/Z26PhQwu5a9ZxiTq9
Granview Highway North (City of Vancouver):
https://goo.gl/maps/auep3gq8w8zQZiFU6
Victoria Drive (City of Vancouver):
https://goo.gl/maps/YiY3MMMZDg1TYgft9
Vanness and Joyce (City of Vancouver):
https://goo.gl/maps/9jeoEzr8VG3qXJzc7
Vanness and Ormindale (City of Vancouver):
https://goo.gl/maps/T1MeodDBQLuajPrS9
Central Boulevard (City of Burnaby):
https://goo.gl/maps/NiDF8LUu4SzYhTo2A
Rumble Avenue (City of Burnaby):
https://goo.gl/maps/gFRqoyGJbNJb2fTcA
Cambie Street and Marine Drive (City of Vancouver):
https://goo.gl/maps/C4S3u3Zd56ykq4a26
Number 3 Road and Cambie Road (City of Richmond):
https://goo.gl/maps/gGRewhQxqf2rqA1Z8
Number 3 Road and Lansdowne (City of Richmond):
https://goo.gl/maps/pS5gKz6dNP5PQQYG6