  Gamma-ray bursts (GRBs) are particle acceleration sites that can emit photons
in the very high-energy (VHE) domain through non-thermal processes. From 2004
until 2018, the current generation of Imaging Atmospheric Cherenkov Telescopes
(IACTs) did not detect any GRB in the VHE domain. However, from 2018 to 2020,
five detections have been reported. In this work, we try to solve the case of
the missing VHE GBRs prior to 2018. We aim to identify GRBs that might have
eluded VHE detection in the past years by the H.E.S.S., MAGIC, and VERITAS
IACTs. To do so, we study GRBs with known redshift detected by \emph{Swift}
from 2004 until June 2022. We first identify all GRBs that could have been
observed by these IACTs since 2004, considering observation conditions and
visibility constraints. We assume a relation between the X-rays and the VHE
gamma rays based on the VHE GRBs detected to date and combine this with the
redshift measurements, instrument response information, and observation
conditions to predict the observed VHE gamma-ray flux from the \emph{Swift}-XRT
measurements. We report findings on 12 bright low-redshift GRBs that we
identify as most likely to have been detected in the VHE domain by current
IACTs. The rate of IACT-detectable GRBs with ideal observation conditions is
$<$1 VHE GRB per year with the current configuration. With its lower energy
threshold and higher sensitivity, this rate increases to $\sim$4 VHE GRBs per
year with CTA.
