[venusiant]

1. TDD can make delivery timelines more predictable, as there is less chance of regressions being introduced as new features are added. This predictability can allow a team to scale up to larger and more lucrative projects.

2. TDD enhances the capacity for necessary refactoring to take place which reduces the complexity of the codebase. By reducing complexity we can increase development productivity.

3. TDD itself can speed up development. A developer will necessarily have to test the feature he is building. Manually testing this feature will be time consuming and repetitive. An automated test allows the developer to quickly test the specific element that is being built in a repeatable and verifiable manner.

4. You are saying that the QA team is not catching all the defects. What else is new, but if you are delivering poor quality product to your customers then this may have commercial consequences in the future, if not already.

5. TDD is best practice and is necessary for the professional development of the team. If TDD is not supported it will negatively impact the ability of the business to retain good developers.

But aside from that, if we are talking about software development inside large corporations, we are probably talking about half-baked internal projects that aren't going to go anywhere due to a variety of reasons. The are probably a whole host of things to change within any large corporate of which the introduction of TDD is but a minor concern.