First of all Virgin Galactic is a trash company that mostly been use to scam investors, they have shown nothing but incompetence using them as a reference point is just a terrible idea.

But there are many other issues with the concept of just not doing human space flight at all.

If you want to do real systematic science and exploration have humans is actually cheaper. Human on mars supported by serious equipment and local labs is simply more powerful. The best results you get when you have real human scientists directly on location.

And the cheap price for science missions is also partially a myth, despite being a second flight of the same architecture Perseverance cost over 2+ billion. We can't spend 2 billion every time we want to get a few rocket samples and then spend many more billions to pick them up. The complete cost of designing a lunar lander for NASA (that is capable of delivering 100x that weight of Perseverance) cost 2.9 billion.

If you want to do really serious science on a large scale on mars, you will have a human station with lab facilities resupply by reusable rockets and space craft, going on expeditions themselves or sending out robots that can bring back samples and be repaired.

In addition, the human component is quite simply politically incredibly relevant. Human rocket launches draw far larger audience, astronauts are the best ambassadors for space. In addition, the technology developed for human in space of has application for humans on earth as well so much of the technology to provide, air, radiation protection and so on is relevant.