The issue is not whether JT will or won't pay tax. He will.
The question is to WHOM (which country) and WHEN (timing of amounts exigible) such taxes will be paid. Deferring tax can often, but does not always save tax.
The Tax Treaty with the US is a highly complex agreement and can lead to some very strange - and occasionally double-taxed - results. In this case he is relying on a very specific section of the Treaty, an exemption (really more of a relaxation) under it.
The best general purpose and non-technical explanation I've seen of it is here:
https://www.wealthprofessional.ca/ne...rtunity/244953
Tax people have known this was likely coming for some time, and yes, whether he wins or loses, it will be applied to others. This isn't likely to show up in the Tax Court of Canada any time soon.