You're assuming that this "first step" has no impact. It does, and a company that receives one of these letters must undertake measures to correct the problem

You're assuming that this "first step" has no impact. It does, and a company that receives one of these letters must undertake measures to correct the problem ($$$) or else face worse sanctions. Getting a warning letter can also hit a company's stock price, cause a reshuffling of management, and other results.