Yeah. The usual reason given is that Mars lacks a magnetic field to shield it from having the atmosphere ablated off into space by solar wind.
Thus they explain the thin atmosphere of Mars, 206,700,000 km from the sun, while ignoring the fact that Venus also has no magnetic field, is only 107,500,000 km from the sun, and still has a hugely thick atmosphere...
Mars had a sufficiently thick atmosphere at one time for the presence of a water cycle. It’s also possible some primitive forms of life appeared at that time.
It isn’t even out of the question that life began on Mars and got transferred here.
But the significant point is that adding an atmosphere will keep the pressure up for a considerable length of time, magnetic field or not.
Of course, if we’re going to the trouble of bringing in an atmosphere, we might find it also advisable to produce an artificial magnetic field.
If we fix Mars, and leave Venus alone, aside from riding around on its atmospheric rivers, those two planets could easily support a billion people each.
Imagine what they would be doing to make a living there!