You've never heard that GPL can hinder adoption? Most codebases simply cannot use GPL code because if they do, they'd be forced to relicense under GPL (obviously). Not everyone wants to do that, even setting companies aside.
Even people who nominally agree with the concept of Free Software might not want to be forced to use GPL. The freedom to choose how to license one's work is also an important freedom, after all. GPL can be confusing, so you can't fault anyone from not wanting to use it even if they agree with the spirit of the license.
(For the record, I use GPL on some of my projects. I don't hate it, but I also like to use MIT on some projects, too.)
Libraries are normally released under LGPL, which allows the use inside your differently licensed code.
A ton of commercial services and products somehow use Linux, the poster child of GPL2, while also running tons of their proprietary code. Python is GPL, and it's all over the place in the computing world.
If you just want to take some code someone else wrote, for free, and alter and meld it into your commercial product, well, yes, GPL does not allow that. I don't think it's a huge impediment for legitimate use.
I'd say that all open-source approaches have their own use cases. Certain things are easier to release under BSD / MIT license, some makes sense to release under GPL, some have to resort to AGPL, to the detriment of commercial adoption. A dual restrictive open-source + paid commercial license can be the best in many cases.
