There are lots of companies and institutions with smallsats/cubesats looking to put them into orbit, but SpaceX came into the smallsat launch market as the 800-pound gorilla, offering Falcon 9 rideshares with prices as low as just $250,000 for a 50kg cubesat to sun-synchronous orbit. That disrupted the small launch market and altered the market dynamics so that small-launch rockets are no longer profitable.

Virgin Orbit couldn't hope to compete with that, at $12 million for 450kg to SSO. ($1.33 million for a 50kg cubesat, if 9 customers would sign up for a Launcherone launch to split the $12 million cost).

Other smallsat launch companies are in similar dire straits, such as Astra, which now doesn't even have a working launch vehicle after they abandoned their Rocket 3.

Relativity doesn't even look like it will be selling Terran 1 small-launch missions but going all in with their development of the bigger Terran R.

Rocket Lab saw the Space Falcon 9 rideshare threat coming at its core business (smallsat launches on Electron). Peter Beck was able to adjust Rocket Lab's business to adapt to the threat, by diversifying Rocket Lab's business into building satellite buses and other satellite components. Beck also took a huge gamble to try to remain relevant in the launch business by developing the medium-lift Neutron to stay competitive against Falcon 9, and it remains to be seen if this high-risk gamble will pay off.

Virgin Orbit is in a particularly tough spot. They have no viable path to a more versatile medium-lift launch vehicle-- Launcherone is the biggest rocket they can hang off a 747's inboard pylon. And they couldn't diversify their business away from small launch like Rocket Lab with its satellite bus and components business.