This seems to be the case in BG3. Maybe more like, Quadratic Wizards, Cubic (or even exponential) Warriors, point is, warrior's power curve is sharper than the caster's.
Casters peak at around early Act 2, when they get access to the Acuity items, Potent Robe and their ~6 level subclass abilities.
High level wizard spells mostly have lower the tier equivalents. The only game changer high level spell is Globe of Invulnerability, I think.
And the biggest limiting factor for casters is Concentration. They can only concentrate on the one spell at a time, and nearly all the fun spells use it.
Warriors peak by Act3, with the Resonant Stone, Bhaalist armor, Terazul, and by the 10-12th level for third attack for Fighters, extra BA for Monk/Rogue, final skill of Hunter etc.
With the Action Surge/Bloodlust/Haste/Terazul, fighter can do like 16 attacks per round, dealing huge damage with each strike if they exploit slaying arrows/crits/vulnerabilities.
Of course, casters also can use extra actions, vulnerabilities and, in come cases, crits. But casters still only have one Concentration. And their damage multipliers are much harder to stack.
Good thing is, they are best when working together. Casters debuff/disable enemies, whilw warriors kill them. So, I consider it a better game design than if casters would make warriors obsolete.