I definitely think what happened is that the Flames valued Grushnikov over Van's 1st round pick.
I'm almost certain Van didnt want to trade any more prospects and was only offering draft picks.
Van needs whats left of their prospect pool to make the team soon as their stars get paid, the likes of Podkolzin, Bains, Raty etc are all key pieces cap wise. Canucks will likely have to walk away from upcoming free agents who are going to get a raise like Joshua, Bleuger, LAfferty etc. Thats why they need to youngsters. Apparently they didnt even want to add prospects for Guentzel.
Vancouver was dangling their 1st 2025 for Tanev, im certain of it, clearly why as well they thought their offer was better than Dallas.