Why is Canadian productivity so low?

Canada has a sub-Italian productivity per hour.
https://www.oecd.org/en/data/indicators/gdp-per-hour-worked.html

When discussing productivity differentials between high income countries the usual explanations trotted out are about small firm size in the service sector (for southern Europe and East Asia) or differentials in adoption of ICT technology in the service sector (for Europe vis the US, see here https://cepr.org/voxeu/columns/transatlantic-technologies-why-did-ict-revolution-fail-boost-european-productivity ).
However, neither of those seem to apply to Canada. Canada follows the same US retail model and many US retail companies operate beyond the northern border; corporate practises seem to be extremely similar and so the broader economy.

What does explain low Canadian productivity, given that it predates the recent surge in immigration and does not seem to be related to workplace protection laws, which are a bit stricter up north but a far cry from basically every european country?