If I sell software with anything like a typical commercial license and I decide to stop supporting it, you're SOL. With the GPL, at least you have the source and can spend money to hire someone to support it.
The GPL emphasizes code freedom over developer freedom. Take a look at Question 6 of the Commercial License page for MySQL:
Q6: What is Sun's commercial license for MySQL software?
A: Sun offers a commercial license for all of its MySQL software that is embedded in or bundled with another application. The commercial license allows OEMs, ISVs and VARs to distribute commercial binaries of MySQL software with their own commercial software without subjecting that software to the GPL and its requirement to distribute source code.
Emphasis mine. If MySQL had been BSD licensed, Monty Program AB could continue to offer a similar service for MariaDB, even though it was not the primary copyright holder of MySQL's codebase. Of course, said commercial software would have to have the BSD license included somewhere in their documentation, per the BSD license's second clause, but this is likely to be far more agreeable than the GPL's onerous requirements.
As far as the trademark is concerned, if I own BobSQL, you can't call your own database BobSQL regardless of how either one is licensed.
You are precisely correct. However, I feel that too many GPL advocates don't think about the ramifications of having to discard the brand associated with the code. "Oh we'll fork it and everything will be fine" is naive, since you now have to "get the word out" about the forked project all over again. And this is only if the copyright holders have abandoned the project, if they continue to develop it, you are now effectively competing against your old established codebase and have more to prove.
Looking back over my original post, however, it does look like I put the branding issues and the 'commercial closed source' issue under the same umbrella, though I meant differently (see: singular use of the word "disadvantage") My apologies.