I believe @melling implied that it would be better if Russia and China could also get humans to Mars.

The U.S. is just so far ahead in terms of space technology. I am sure one day other countries will catch up, but it is going to be awhile.

It's a matter of will, not necessarily of tech. The US has shown it lacks the will to achieve its former dominance.

Because then space exploration would be a political issue again, and we'd have another space race (hopefully)