Respectfully - there's so much misinformation in this post, I'm not even sure where to begin. But let's try to clear up some of the misconceptions:
Well, yeah - obviously. Who said it's just a matter of "declaring" Arizona as Matthews' residence? There are specific steps that Matthews needs to undertake in order to structure his affairs. If he does it, the benefit is saving (ballpark) a million dollars per year.
Here's a
good article that goes into some of the considerations that are relevant.
I also specifically address the question "why doesn't every NHL player do this?" in
this post. (The short answer is - a lot of facts need to align for this strategy to be beneficial).
Just so that everyone can follow, you're now talking about an unrelated topic - the RCA.
Deferral is one of the most basic forms of tax planning. Would you rather pay $5M in income tax today, or pay $4M, and invest the additional $1M and let it compound over years (or even decades)? It's not a trick question. Tax advisors have a professional responsibility to their clients to make them aware of ways they can defer tax.
Saying that an RCA "just" provides deferral is like telling a doctor not to treat someone's cancer because it "just" defers their death by another decade.
For the record, we have no idea if Matthews has an RCA or not. Also, we don't actually know if Matthews has taken the position, in his tax filings, that he's a non-resident of Canada. All we can do is speculate, and note that he's structured his past two contracts in exactly the way that would facilitate that strategy).
Again, you're confusing yourself because you're mixing up different, unrelated tax planning strategies.
The main tax planning tool would be for Matthews to structure his affairs in order to be a resident of Arizona (for tax purposes). There's an enormous amount of case law about determining an individual's residency. In contrast, CRA is going after Bautista for whether his RCA contributions are "reasonable". That's a vague concept which hasn't (yet) been refined through dozens of court cases. You're conflating two separate topics here - and the one which is most relevant to Matthews has been well defined by case law for several decades now.
I think this is your attempt to discredit subject matter experts because you either don't like, or don't understand, how tax planning works.
Look, tax planning can be a very complex area. This website is about hockey, not finance, and I don't fault anybody for not knowing about how this works. But you should ask questions here, rather than making declarations about a topic that (respectfully) you clearly don't understand.