A balanced approach
In any design and manufacturing process, the earlier a problem is caught and dealt with, the more cost-effective the process and the better and safer the product is likely to be.
In the case of EMC, designers and engineers usually need to have reference material such as IEC standards, specifications or technical reports available to them from the very beginning of the design cycle, both for their own benefit and that of users or customers.
TV screen covered in "snow"
It is in response to this need that the IEC has adopted its specific approach to EMC standardization based on balancing the controllable emissions and the immunity of equipment to reach a compatible situation.
The IEC also aims to make the necessary EMC documents available to all interested parties if and when they need them, i.e. in advance of a crisis. In contrast with a palliative approach that would start developing standards only once the urgent need arose, this allows manufacturers to know early which emission levels their products should achieve, for example, and which immunity tests should be carried out.
This forward-looking aspect of IEC EMC standards is particularly true for the general publications that apply to all electrotechnical products, because these can be used and referenced in the development of standards oriented more towards specific products or families of products.