I mean, yeah, that's sort of been the issue for much of that time, that the amount of science they could do on a short jaunt of a few days or weeks doesn't justify the many months spent traveling there, though there is science that can be done in transit (though it's largely the same things that can be done in orbit around earth, anyways)

There are a number of different proposed methods of doing it, on different time scales, but I really dig the ideas proposed in Mars Direct , which could have even feasibly launched in the 2000s.