Using the QCD hybrid (moments-Laplace) sum rule, we show semi-analytically that, in the limit M b → ∞, the q 2 and M b behaviours of the heavy-to-light exclusive (B → ρ (π) semileptonic as well as the B → ργ rare) decay-form factors are universally dominated by the contribution of the soft light-quark condensate rather than that of the hard perturbative diagram. This phenomenon can invalidate the M b -behaviour of the form factor from the conventional light cone approach. To leading order in1M b , the form factors behave as 1f B M b , while they reproduce the HQET expectations at q 2 m a x . The QCD-analyticq 2 behaviour of the A B 1 form factor differs significantly from the naive polar form, as it decreases for increasing q 2 . The other form factors increase slowly with q 2 (they can be fitted by a polar form) as their q 2 -dependence is only contained in the non-leading terms in 1M b . However, due to the previous non-leading q 2 -dependent terms, our results indicate that it is misleading to combine the polar form of the form factor with the HQET result at q 2 m a x , in order to deduce theM b -behaviour of the form factor at q 2 = 0. Numerically, we extract with a good accuracy the ratios: V B (0)A B 1 (0) ≃ A B 2 (0)A B 1 (0) ≃ 1.11 ± 0.01, andA B 1 (0)F B 1 (0) ≃ 1.18 ± 0.06; combined with the world average value of f B + (0) or/andF B 1 (0), these ratios lead to the decay rates: Γ B → ρ e ≃ (4.3 ± 0.7) V u b 2 10 1 2 s - 1 ,Γ B → ρ e Γ B → ρ e ≃ 0.9 ± 0.2, and to the ratios of the ρ-polarised rates:Γ + Γ - ≃ 0.20 ± 0.01, α 2Γ L Γ T - 1 ≃ - (0.60 ± 0.01).