I don't agree at all. The kinds of regulations that define how buildings are made are all pretty compatible with traditional building techniques. Obviously modern houses need to have insulation and air tightness, but that's not incompatible with block and timber construction used in old houses.
The cost of complying with regulations when building a house isn't even particularly high. It's stuff like "use x thickness of insulation" and "design it with a protected fire escape route". It doesn't cost much at the design stage to take those into account. The dominating cost is materials and labour.
What regulations stop people putting ornamentation on their house?
It is not just regulations.
It is because land + regulations are expensive, cutting costs is important. Now we also could count high interest rates.
So, building as cheap and fast as possible is important to stay afloat. Example: making house from prefabs is cheaper and faster comparing to building using bricks + pro brick laying technics (i.e. what you can call ornamentation).
Besides, we should also consider that while saying that ornamentation is good to have, it does not mean it would fit all the people.
Good idea is to have regulations limiting what exactly you can build in historical centers of european cities.
The cost of complying with regulations when building a house isn't even particularly high. It's stuff like "use x thickness of insulation" and "design it with a protected fire escape route". It doesn't cost much at the design stage to take those into account. The dominating cost is materials and labour.
What regulations stop people putting ornamentation on their house?