The so-called Awakening Celestial Sword image did not equal to someone meeting Meng Qi and remembered him. It was not that simple. Otherwise he need not worry about adjusting the image, etc., if he only needed to adjust it according to the projection feature.
To influence a few people's opinions, Meng Qi could get it done easily as a puppet. Or he could just arrive in this world.
But Meng Qi assumed that to foster an image that corresponded to his illusory additional self, he must leave a legend behind in this world so that more than a stable image could be fixed in different generations like an everlasting stamp that would not easily be washed away in the time river. This would take at least 60 years and three generations' efforts.