Kinder Morgan were the original owners of the pipeline. After over a decade of legal battles and never ending studies they walked away from the project. Trudeau's bill C-69 was widely viewed as the 'no pipelines' bill. Pipeline was sold to Govt of Canada for $4.7B with an estimated cost of $5.4B to complete.. The actual cost to complete the TransMountain pipline was $34B. That is kind of crazy.
Now Carney's job is to convince private corporations it is safe and worthwhile to invest in the energy industry again. We will see if it happens.