happy to discuss your points.
Doing Business does not sample firms for two main reasons. The first pertains to the frequency with which firms engage in the transactions captured in the indicators, which is generally low. For instance, a firm goes through the process of starting a business once in its existence while an incorporation lawyer may do several dozen such transactions in a year. Therefore, the experts providing information to Doing Business are better suited for assessing the process of starting a business than individual firms. Second, most of the information gathered through the Doing Business questionnaires is of a legal nature which firms are unlikely to be fully familiar with.
This method does demand a very rigorous review of the responses of more than 35000 experts around the world. Even if it was methodologically possible to sample firms directly, it would be practically near impossible to create meaningful ratings at the country level as one would need a huge random sample.