You dont need people to do a sample return. Hence nasa has a plan to do sample return with robots. Starship will very likely be second or even third to return samples from Mars, but will also be very likely to return exponentially more mass when it does. The distance isn't even the big problem when it comes to robotic missions. When it comes to a lunar rover or a Mars rover the ability to travel beyond earth orbit is the easy part. It's the keeping the rover working on the surface part that is hard.

If you can land on the moon, you can land on Mars. It may not be immediately but it can be done. Especially with our vast experience landing payloads on Mars already. Since spacex is contracted to land people on the moon, and that requires being able to land on earth, when that is done it is almost guaranteed to leave us with the capability to land large payloads on Mars shortly after.

If you think taking humans to mars is more than 50 years away then I feel like you haven't been actively looking at all the pieces that are falling into place. We're much closer than 50 years. Probably closer to 20.