  Recent experimental studies on strongly disordered indium oxide films have
revealed an unusual first-order quantum phase transition between the
superconducting and insulating states (SIT). This transition is characterized
by a discontinuous jump from non-zero to zero values of superfluid stiffness at
the critical point, contradicting the conventional ``scaling scenario''
typically associated with SIT. In this paper, we present a theoretical
framework for understanding this first-order transition. Our approach is based
on the concept of competition between two fundamentally distinct ground states
that arise from electron pairs initially localized by strong disorder: the
superconducting state and the Coulomb glass insulator. These ground states are
distinguished by two crucially different order parameters, suggesting a natural
expectation of a discontinuous transition between them at $T=0$. This
transition occurs when the magnitudes of the superconducting gap $\Delta$ and
the Coulomb gap $E_C$ become comparable. Additionally, we extend our analysis
to low non-zero temperatures and provide a mean-field ``phase diagram'' in the
plane of $(T/\Delta,E_C/\Delta)$. Our results reveal the existence of a natural
upper bound for the kinetic inductance of strongly disordered superconductors.
