Let
F be a separable integral binary form of odd degree
N \geq 5. A result of Darmon and Granville known as ‘Faltings plus epsilon’ implies that the degree-
N superelliptic equation
y^2 = F(x,z) has finitely many primitive integer solutions. In this paper, we consider the family
\mathscr {F}_N(f_0) of degree-
N superelliptic equations with fixed leading coefficient
f_0 \in \mathbb {Z} \smallsetminus \pm \mathbb {Z}^2, ordered by height. For every sufficiently large
N, we prove that among equations in the family
\mathscr {F}_N(f_0), more than
74.9\,\% are insoluble, and more than
71.8\,\% are everywhere locally soluble but fail the Hasse principle due to the Brauer–Manin obstruction. We further show that these proportions rise to at least
99.9\,\% and
96.7\,\%, respectively, when
f_0 has sufficiently many prime divisors of odd multiplicity. Our result can be viewed as a strong asymptotic form of ‘Faltings plus epsilon’ for superelliptic equations and constitutes an analogue of Bhargava's result that most hyperelliptic curves over
\mathbb {Q} have no rational points.