You figure an aircraft's modernity based just on just it's range?? There is fuel consumption, safety, maintenance cost, etc... It is not on par with Boeing and Aribus' modern designs but it is not far off as a modern civilian airliner and a better start than what really any other nation could achieve. China basically just began its civilian aviation with C919, a foot in the door and already guaranteed to be a success with China's (and likely Russia's) domestic market size, taking away Boeing and Airbus' funds for thousands of airplanes they would have sold to China to further thier lead. The C919 can turn that tide, retain those funds in China and begin China's ascent into civilian aviation.
For the better part of the last few decades, China has been focused on military aviation and has become one of three nations, behind only the US, to produce a 5th generation stealth fighter. That is an indication of what China is capable of, not some skin deep comparison of flight range.
Where'd you get 2040's from? The same "few months = 10 years" Western wishful thinking you used on the semiconductor thread?