if you have less tests and you end up testing only the ones with extreme symptoms then you have also more tests per case.... in their case the tests are only for a diagnostic tool in hospital as they dont have the resources to do contact tracing which is very test intensive

many poor countries get also tests from china, which 80% do not work

and if u are a rich country, the question on how much tests you have will depend on how many tests your allies produces or if u produce ur self.