IMO one of the biggest lessons of the past decade in hockey is that short "Cup Windows" are total BS.
I remember Penguins fans desperately wanting these two because by the time the contracts weren't worth it the "window" would be over anyway. https://twitter.com/RussoHockey/status/1279428876356255749?s=20
This was based on the idea that those teams would only be contenders while Crosby/Malkin/Ovechkin/Stamkos/Bergeron/etc. were in their primes. But here we are, eight years later, and many of those teams are still contenders.
But "window" thinking leads to moves that destroy a franchise's competitiveness, like the Blackhawks. If you're a team with a star young core like Toronto or Vancouver, assume that you should be a contender for the next 12 years and act accordingly.
You never know if your team will draft a Pastrnak, Guentzel, Kucherov, Point, Parayko, etc.