Very weird comparison.

GPL was made in response to restrictive commercial licensing. Yes is uses the same legal document (a license): but is made in response!

So is propriety seizes to exist, then it's not a problem GPL also seizes to exist.

Also: it's quite obvious to me that IP-law nowadays too much. It may have been a good idea at first, but now it's a monster (and people seem to die because of it: Aaron Swartz and Suchir Balaji come to mind).

There are zero guarantees and commercial software uses GPLd software as parts of their products all the time. Licenses do not work and you shouldn't respect them whenever you can.