Yes this trade would make the flyers better for the next 2-3 seasons, but are they more or less likely to win the cup in the next 6 years if they make this trade? If they don't have a #1 D it's not happening, with or without Huberdeau.
What it comes down to is that the Flyers current rebuild is predicated on 2 of Provorov/Sanheim/Morin becoming legit top paring D in the next 3 seasons. That's what it will take for them to have a cup window before Giroux fades. Trading Provorov essentially means throwing the current rebuild out the window, which is why it would take a player like Barkov coming back to be worth it.