Welcome to the SDMB! This thread is about Starlink and similar satellite constellations, but we do have another thread where we talk about many space things, including smallsat launchers. We should probably continue the conversation there if you want some involved discussion.
Overall, although I am a supporter of these small launch companies, and always look forward to their test flights, I don’t see how the market supports more than one or two of them. Among all of them, Rocket Lab is the only one actually making regular flights. Virgin Orbit has made a couple of flights to orbit, but doesn’t yet seem to be a sustainable operation. Astra and Firefly have both recently made test flights which failed to make orbit. That’s ok–space is hard–but the longer it takes, the less likely they are to succeed as a company.
There are many more prospective smallsat launcher companies out there with an even small presence, and it’s hard to keep track of them. I wish them all luck; they’ll need it.