Kingdom Come: Deliverance dev explains that the RPG had to take place at a very specific point in time - so that there aren’t any guns

gamesradar.com:

According to series creator Daniel Vavra, Kingdom Come: Deliverance is set during a very specific period of European history to make sure there’s enough weapon variety without having to add guns.

When creating a fictional medieval world, there’s typically no issue with the technology and weapons you add into the game since they aren’t tied to anything specific in the real world - you don't hear anyone complaining about the lack of muskets in Elden Ring after all. For Kingdom Come: Deliverance, however, its real-life setting meant that it had to take place at a very specific point in history.

“The first half of the 15th Century is the most interesting because a lot of stuff happened at the time”, explains Vavra in an interview with PC Gamer. Given the game’s focus on history, its setting was of huge importance to the story, with the early 15th Century marking a period of relative turmoil in Bohemia, now modern-day Czechia. 

But beyond simply being a good setting for the game, the time marks what is, for Vavra, the most interesting period when it comes to medieval armour and weaponry. Set at the start of the 15th Century, Vavra notes that it’s at a point in time where technology has advanced far enough to have enough weapon variety for the game. “100 years sooner, it would be much less diverse in terms of options for cool things like armour and weapons” he explains.

But perhaps more important to him than the weapon variety this time period affords, it’s also early enough in history that guns haven’t made their way into the arsenals of a warring Europe. “50 years later, there would be gunpowder weapons, which is too much”, he begins. “It would make armour obsolete.”

“This kind of gothic period is the most interesting in terms of knights and stuff.”, Vavra concludes, and he’s absolutely right. KCD’s historically accurate medieval combat has been a major selling point for the game, and it’s hard to feel that the combat would have been as impactful had you been able to