I am in the energy industry in the US and can provide a little insight into the "disconnect." Canadian crude is famously in its own little world in terms of pricing. It is choked by pipelines which are currently at full capacity on all sides with no easily accessible port city. The only outlet for excess crude is rail which is A) expensive, B) more risky than pipelines and boat, and C) extremely socially sensitive. Canadian crude industry has more or less been under the thumb of USA pipelines and refineries for a while because it is the only significant outlet. IE there is very little competition between buyers that can help drive prices up. Canadian crude producers' earnings are sort of metered by what US refineries are willing to pay.

That being said, multiple pipeline projects are about to help change this over the next couple years, significantly increasing Canadian crude capacity to Vancouver which will help open it up to the world market. It is still going to be at somewhat of a discount compared to other crudes, but this will help.

One other thing to note that may be weighing on Suncor's pricing is the perception society has on oil sands. To produce oil from these sources is intensely carbon intensive (equipment requirements, processing, etc) before it even hits a refinery. So if there ever is a concerted push to tackle atmospheric carbon, one might expect oil sands to be one of the earliest victims.

As for Suncor as an investment, it may see some great really stellar earnings increases once the increased pipeline capacity comes online. This is assuming the economy has recovered from COVID by then.