These are all different rockets, several not interchangeable by mass - e.g. Electron is pretty light, SLS is pretty heavy, some others are still smaller than Falcon 9. We'd like them to prosper, we don't have enough launchers - but to replace the capabilities of retiring Falcon-9 - not to mention Falcon Heavy - many of those rockets will have to demonstrate reusability and ability to launch frequently, which might take time.

Take 'first flight' with a massive grain of salt. And the 'return to flight' with a smaller amount.

And the issue is that many of these are booked out and have backlog. So even when they return to flight, its years before they can take on new contract.

And many of them can't fly many of the required missions for NASA or DoD anyway.

Nova has already been renamed Nova Pathfinder and is likely only going to be flown a few times before they will switch to a larger rocket.

Yes it does, and the article says why and how. Other space agencies... that's a very different question. Only China can be comparable to NASA in terms of breadth of space initiatives, and China has their launch industry. Everybody else mostly doesn't use as many launches per year as SpaceX is capable of doing.

I guess the answer depends on whether you see NASA's goal as "to do cost-effective science" or "to do cost-ineffective rocketry" (since the express purpose of e.g. the SLS is to appeal to congress by providing local jobs as economy stimulus)