At first, I thought that it was closing for a "bad" reason but what you say is logical. But, why would they list alternative services if they would eventually come back?
The other services I mentioned in the email are Selenium based so hopefully users can transition. Even if GTI comes back later, we felt it was right to offer users some alternative.
Edit: Just to clarify, there are no plans to include GTI with any of Red Gate's other products. Forgot to mention that when I first replied.