> Force-field was innovative.

Yes, although the shields were fudged somewhat to allow knife fights. It would also seem that mankind lost the ancient secrets of body armour.

> Like, just use a gun. Whatever you were going to attack with, put that in a gun, and attack at 45rpm, 3000 ft/s.

There was even one Dr Who episode where the Daleks replaced their beam weapons with machine guns [0]. Although only because there was some sort of 'unknown force' that disrupted the guns without affecting the other Dalek systems.

[0] https://tardis.fandom.com/wiki/Death_to_the_Daleks_(TV_story...