  Indirect signs of new physics beyond the Standard Model may be appearing in
$B \to K^{(*)}\mu^+\mu^-$ decays. If confirmed, the title question will be of
paramount importance in determining the strategy for future colliders. We
answer it by estimating the sensitivity to minimal, anomaly-compatible
$Z^\prime$ and leptoquark models at the high luminosity LHC, 27 TeV HE-LHC, and
100 TeV FCC-hh; this conservative analysis outlines an upper bound on the
available parameter space and the conditions for a reasonable guarantee of
direct discovery.
