As the folks at the PBO mentioned, I think there are two parts to that.
The first part is that not as much money has flowed as was expected at the time of budget 2016.
The second is that the economy wasn't at the same stage of the business cycle as it was at the time of budget 2009 when the fiscal multipliers included in budget 2016 were originally released. At that point there was very little risk of seeing a dramatic increase in interest rates on the part of the Bank of Canada.
Also, the gap between Canada's current and trend levels of output was much larger then, so each dollar of infrastructure spending would have had a much larger impact on the economy, because you had a lot of economic slack. You had a lot of resources that were freed up in the construction sector, because people were not investing in housing, were not investing in private infrastructure, and also were not necessarily employed at that time, so it employed a lot of resources that had become available because of the crisis. Had we had as large an output gap, potentially the impact would have been dollar for dollar as significant as it was back then.