This is an over-exaggeration generally only argued by D3 haters that have a gross misunderstanding of how the game works.
Spells scaling off of your weapon’s damage doesn’t mean you’ll always want a better weapon. Why? Because the increase gained from a higher base damage weapon can be marginal relative to the increase gained from affixes on your current weapon. We literally see this in D3. If you’re playing a Shadow DH, good luck using a crap rolled Primal Karlei’s Point over a god roll Ancient one.
This argument is only made by people who refuse to actually do the math to support their argument. It’s an entirely philosophical discussion that can be invalidated with simple math. It’s only actually true if the increase in weapon damage is MASSIVE, which in reality never actually happens.