There are space companies other than SpaceX which participated in the same contracts and were nowhere nearly as successful.

* Boeing did not yet deliver commercial crew. * Antares rocket did not expand beyond ISS delivery. * Blue Origin is not yet flying, despite immense funding. * Virgin Galactic did not yet fly any customers.

The other great space launch success in the last decade was RocketLab but they're far too small to be relevant to SLS.