Thorium, might be a bit different of an issue.
Just because it has been done before doesn't make this routine. More importantly, that there are now two companies with proven track records of delivering bulk cargo to the ISS, it implies that a disaster or major engineering flaw on one spacecraft won't stop the other spacecraft type from continuing to fly.
Oh, I am a big fan of redundancy, esp. for space systems. NASA under Nixon, reagan, and W proved that we need multiple launch systems to be in space constantly. However, when it comes to delivering cargo to the ISS, there is Russia, and ESA that deliver on on Russian ports, and SpaceX, and Japan that use berthing of the west. IOW, we already had redundancy in terms of cargo to the ISS. What is REALLY needed right now, is human flight to be restored.
Now you pointed out 2 of the options which is CST-100 and actually, Dragon Rider. But there is a 3rd which is SNC's Dream Chaser.
And when one of these fly first with a human cargo, they will be historic since it will be the first private system to LEO. The second that follows it will NOT be historic since, like COTS, CCXDEV is designed to put multiple American human launcher systems into space. The 2'nd and 3rd will simply be following.
Oh, I am fine with it being posted. Just noting the fact that it was NOT historic, and that OSC really did not do that much. In fact, they did far less building then even Boeing and L-Mart do on their systems.
Only through hard work and perseverance can one truly suffer.