Not saying they get it right even most of the time, but for my flight last week from BOM to YYZ I was informed almost 12 hours in advance that the flight was delayed due to late inbound (snow in YYZ delaying departure) and I was also proactively protected on a later flight to YVR.

The gong show at YYZ due to a down gauge from a 77HD to a regular 777 was an entirely other story though.