Answer: Doership -- is what makes Vedas as scoped to 3 modes.
BG 2.45 - Veda-s are subjected to 3 modes of material nature (Sattva, Rajas, Tamas); O Arjuna, become free of these 3 modes, free of duality, ever situated in "constant-ness"; free of gaining support [and] self sustained
Comparing Vedas (public domain) and Gita (private domain), is like comparing apple and oranges! They are Not competitors.
Veda-s and many subsequent philosophies derived from it, assumes "Doership". i.e. they provide iterative teachings about Dharma (do-able), Adharma (non-doable), rituals, Karma-s and all such aspects.
While Gita refutes "doership". It says that the 3 modes are responsible for any Karma happening. One doesn't dictate, what Karma he/she will do.
BG 3.27 — All actions (karma-s) are enacted in Prakruti by  modes (guna-s). Bewildered with identity, the self(Atma) believes "'I' am the doer".
According to Veda-s, a knowledgeable person may have to follow what is Dharma, which is caused by influence of Sattva and be aware of Rajas (cause of Adharma) and Tamas (cause of Vidharma).
While Gita says that a knowledgeable person knows that he is not the doer! Only 3 modes are acting, by themselves.
BG 5.8, 5.9 — "'I' certainly don't do anything" is thought by knower of elementary (tattva gyAna) - even while seeing, hearing, touching, smelling, eating, moving, dreaming, breathing, talking, discarding, accepting, opening, closing; -- "Senses only are acting in the subjects of senses" - is understood.
Since Veda-s teach that a person "should do this, should not do that", they are limited to 3 modes of nature. In fact, in any plane of world, everything is bound by 3 modes. So Vedas are well placed in their teachings.
Gita doesn't belittle or criticise Vedas. It just says for what purpose Vedas are meant for. However, the supreme nature of Atma is beyond this 3 modes and any purpose.
BG 7.13 — These whole universe being bewildered by the nature of these 3 modes, doesn't know "Me", who is above [them], the transcendental Indivisible (Atman).
If the world (heaven, hell, earth, ...) is some sport, then Vedas are rules of that sport. If you hit like this -- it's foul, if you hit like that -- it's a point, one should play like this, one should maintain decorum, use these instruments, ...
Gita says that the whole sport is spot fixed!