Land acquisition will be lost in certain regards if the ROW changes (e.g. not building Eau Claire), and when I spoke to utility work I meant all of the underground utilities moved over the last three years to accommodate tunnels. Of course it's not 100% wasted, but we're talking about a lot of money and effort here. In what way does it make sense for the city to staff up employees for a mega project and not use contractors? Industry would never do that, it doesn't make sense to hire FTEs for mega projects... What do you do, lay them off once the projects done? Not following your logic here.
Well at a high level, the logic is "don't build mega projects".
It may end up taking longer to build the line from end to end, but it should be somewhat more efficient as institutional knowledge is built. Knowledge that can be used on other smaller projects like red or blue line extensions, or planning for a fourth line.
As a simpler example, if a city decides to build its first road interchange in 10+ years, knowledge on how to do so likely doesn't exist in house, it will have to be learned or hired in.
Along the way, unexpected caveats will be discovered and have to be accounted for, (ie. something to do with local soil conditions) which will likely delay and add costs to the project.
Once completed, if there are no other interchange projects to work on, the team will be disbanded and the institutional knowledge lost.
When a new interchange project is stood up 10+ years later, many of those caveats will have to be relearned, again at unforeseen expense.
However, if a city has a steady stream of interchange projects to work on, the institutional knowledge doesn't get lost, and successive projects may even become faster and cheaper as more efficient methods are discovered via repetition.
To your comments on the land/util costs, if the revised project uses 2st for an elevated route, much of that work may have been necessary anyways, so very little would be lost.
Will the province's consultants be savvy enough to factor in nuanced detail like that?
I won't bet on it, but I'll hope so!