Crossbows had existed and they had been through several evolutions in the current era. The deficiencies of the crossbows were too severe to make them practical, however. The shooting range was too short and the bow weight was too high to be carried around. There were specific requirements for the crossbows to be used with their surroundings. They were not easily maintained and they cost too much effort on the craft and money…
For various reasons, only a small portion of people could afford to use crossbows.
Jiang Pengji wouldn't want to use crossbows, even if they were widely implemented.
She examined the half-finished crossbow; it turned out that the arms, body, strings and triggers all fit with the data she gave.
With her modifications, it would shorten the excessive reloading time which would, in a way, enhance the the flexibility and maneuverability of the bow.