The goal of GPLv3 (and GPLv2 as intended by several of the authors, for that matter), is to ensure that end users have freedom to use the devices they have purchased as they see fit. Suppose a company has patented some algorithm, and has implemented that algorithm in a software project that also uses GPLv3 code. When distributing the software, they make the code available, but only license the patent on the condition that the code is run without user modifications. This infringes on user freedom, because there is no way for the end user to control the software they are running.
For GPLv3, it is important to remember that the primary goal is to protect user freedom. Everything else follows from that goal, specifically in closing several loopholes that were unintentionally present in GPLv2.
> is to ensure that end users have freedom to use the devices they have purchased as they see fit
not really. Nobody can or wish to dictate how someone sells a product.
GPL is about GPL'ed code. not products.
> Suppose a company has patented some algorithm ... that also uses GPLv3 code
you keep moving the goal post. Remove GPL from your example!
If that "some algorithm" was built on top of someone else's proprietary (and patented) work, wouldn't they have to satisfy that entity desires on how it wishes to license their work?
The ONLY difference is that GPL only requires that you make your work available under GPL. Easy. Other entities might ask for money. Others, such as apple, would just tell you to F off and you'd never be able to sell the code or the product. Which one is more restrictive or worse?
For GPLv3, it is important to remember that the primary goal is to protect user freedom. Everything else follows from that goal, specifically in closing several loopholes that were unintentionally present in GPLv2.