“The numbers of cases that are publicly reported every day do not represent the actual picture” There is not a single country in the world where the publicly reported data is the actual picture. By definition. Note that the RIVM never claims that their numbers are the complete picture either, on the contrary. The reported numbers provide an actual picture of what is measured only. The context of which differs per country (in NL case they chose what can be usefully measured given the number of tests available, which by the looks of it means testing to keep hospitals as controlled an environment as possible, to protect staff from falling ill so they can keep working). To a certain level it makes sense: if we all stay home, it doesn’t add any knowledge at all to test for Corona if you or me develop symptoms, as long as you stay home and care isn’t yet needed. We’re already isolated at home anyway, and there is no active cure, there’s only a need for confirmation when hospitalisation comes into the picture then. Until that point self-reporting provides as much information without reducing the limited number of tests available. Testing must yield useful information in the sense that it provides agency in decisions, if it doesn’t it is noise not data. Testing you or me while we’re at home is such noise in the current context it seems.
Here in NL it would be of interest to see more of that current context than the RIVM is currently communicating, even though they could and I think they should. They also have a history of such meagre communication. Hence my conclusion it isn’t a lack of data per se (if you know how your data is insufficient then you are in a position to use that to create better insight.), but the lack of communication (publishing all available data, its context, the models used to work up from the collected data to an overall assessment of transmission speed and transmission hotspots etc etc).