Missing a milestone is usually more than a minor hurdle within industry. For a project missing milestones as indicated in your post would waste company financial resources. However, this is not the extent of the damage, along with financial resources being strained missed milestones can delay a project and take away employee resources as well. For example, if a certain project missed a milestone and therefore needed a team of engineers to stay on longer to complete the project, this would drain from the other tasks/projects those employees could have been working on. Therefore, it can lead to a chain reaction in other delays within the company and sometimes this leads to companies pulling the plug on projects altogether and taking the losses.