Chen Xin's upgrade ability indeed holds extraordinary significance for a nation, but it is not indispensable.
The country can develop without Chen Xin, and having Chen Xin merely accelerates the development process.
To make an analogy, it's like playing Stellaris; at the start, you find a research hub that can provide you with a substantial amount of research points each turn, allowing you to shorten the time needed for technology breakthroughs from dozens of turns to just a few or even one turn.
This indeed allows you to gain advantages and lead quickly, but it does not bring significant short-term improvements, because converting technology into power requires time.
Regardless of colonizing other planets or building fleets, everything requires a large amount of resources, energy, and most importantly, time.
And these are not things that can undergo a qualitative leap merely by simply enhancing technology.
