什么理论说经济增长的原因是消费啊？

Yes, the question by second floor is pertinent: why should growth be always be pulled by consumption, if a country is poor and there is not enough capital stocks available?
Don't people need more capitals to be more productive and earn higher income?
The premise is incorrect, or in another word wrong.
Don't be fooled by those arguments.
They are secondary economists in nature.

可支配收入好没达到一个基准线当然无消费能力啦

首先一般来说穷人的边际消费倾向低，再者中国社会保障体系不健全，使得民众对未来的生活没有信心，自然要储蓄以求防患于未然

应该还是消费占大头吧