NASA chief suggests SpaceX may be booted from moon mission

Artemis is a joke. You can tell this is politically motivated by their stance on SLS. If they were serious they would give Spacex the SLS contract for being years and years behind schedule.

You don't want to rely on a single supplier for critical infrastructure. Their management can extort you, their failures leave you with no backup plan, if they go bankrupt you're really screwed.

Keeping multiple companies capable of building it alive is essential.

I'm not actually sure that having multiple suppliers reduces extortion? If you have a policy of "no single supplier", then supplier #2 can extort you just as much as supplier #1 does under a single-supplier policy, because you have no choice but to keep funding them.

I'm pretty sure this is what's been happening with Blue Origin: in 25 years they've delivered close to nothing, but they keep getting contracts because "we need a SpaceX alternative". What is that if not extortion.

(EDIT: the sibling comment correctly points out that Boeing is an even more obvious case. Starliner is a money pit, but we have to keep throwing more money down it so that there's no single supplier)