Actually, under the law, it is pretty clear.

Is it a taxable supply being provided in Canada?  Yes -- If so, it is the VENDOR's responsibility to collect and remit the tax.   If they didn't collect tax in the past, they are responsible to remit (and try to collect from customers - good luck with that).

If they are a registrant, they are eligible for input tax credits on supplies purchased in Canada.

All it would take is for CRA to start an audit then a court case against Netflix, Google, et al.

Realistically, a logical settlement would be for CRA and the US multinationals to cut a deal to apply the tax on a prospective basis - with a 3 month delay to allow for systems modifications.

That would be tax fairness and the consumers of their service (be it shows or advertising) would pay the tax that they would otherwise have to pay if they bought it from a Canadian Supplier.

Particularly easy in Netflix's case, as customers now need to be customers of Netflix Canada, not the US versio