Yeah well honestly the lack of a magnetosphere is the least of your problems. Most radiation on martian surface is blocked anyways by whatever thin atmosphere there is.
The real problem is the difficulty to get water, the difficulty to grow basically anything, the difficulty to set up functioning greenhouses, the difficulty of ... whatever.
Because that would definitely make a lot of things far faaaar easier. Also, i'm not sure, but i think a lot of the great discoveries/data measurements were taken after 2000? Like, mineral-water in rocks across the planet.