Indeed, NASA stopped launching rockets with the space shuttle. But that was the single best decision that NASA ever made. The space shuttle was an extremely expensive death trap. (It was damn cool, but a terrible way to get to space)

It sounds concerning to put all the egg into the basket of private enterprises.

You can blame the trump administration for that, with their commercial cargo and commercial crew programs. But the truth is, NASA has always heavily relied upon private companies, it’s just that in the past they were all defense contractors (Boeing, Northrop, lockheed, rocketdyne, ULA). The other annoying truth, these commercial programs have actually been wildly successful (except in the case of Boeing’s participation).

But it’s been wildly successful in a few respects, one of which is that nasa has been able to focus on exploration again. Without having to support the huge costs of the shuttle program, they’ve been able to put a lot of their money into landers, interplanetary probes and space telescopes. I think we have more ongoing exploration missions than ever before. The Europa clipper mission launched just yesterday (on a SpaceX Rocket coincidentally). https://science.nasa.gov/mission/europa-clipper/