  We performed state-of-the-art QCD effective kinetic theory simulations of
chemically equilibrating QGP in longitudinally expanding systems. We find that
chemical equilibration takes place after hydrodynamization, but well before
local thermalization. By relating the transport properties of QGP and the
system size we estimate that hadronic collisions with final state
multiplicities $dN_\text{ch}/d\eta > 10^2$ live long enough to reach
approximate chemical equilibrium for all collision systems. Therefore we expect
the saturation of strangeness enhancement to occur at the same multiplicity in
proton-proton, proton-nucleus and nucleus-nucleus collisions.
