Am I ruining my world by making a strong code of chivalry?

I've written a story in a fantasy setting (it's fantasy with magic and mythical creatures and gods and the whole nine) and I wanted for this setting to be perpetually medieval-esque. <br><br>I was working out all the little things that make a perpetually medieval world, but it was so unlikely to happen. All it takes is one guy who invents something that makes the king wealthier than he already is, and with the money he can employ dozens of people to expand his domain, fund his wars, and build his cities. All that will end up happening if one person protests against the system. <br><br>I think that all it would take is a clever person and the whole medieval system would collapse. I can't have that happen because that would stop my story from being able to happen and that story is the reason I'm building the world, so I need to perpetuate a system where no one in the story can upset the status quo.<br><br>I was researching chivalry codes and I think I can extrapolate from those and make a code that stops people from getting too smart, stops empires from expanding, stops cities from getting too strong. But I'm worried that I'm going too far and that the code will be too artificial or that the people will not believe the culture is real.<br><br>I've got a few other things that keep these factors in check, but I'm not sure if perpetuating a chivalry code like this is going too far in ruining my world.