Normal COMMERCIAL games usually take 3-5 years to produce, usually the time is 3 years, and that's 30-100 persons, if not even more, working on a single game.
R-X team is like... Dunno around 15-30 persons? I'd say they are making very good progress, very fast and judging by the info they have given to these forums, also very high quality. (Not to meantion they are doing this on their free time and not as their full time job on which they will spend 8 hours of their day 5 days a week.)