LGPL v3 is _really_ complicated. That's a red flag for a lot of corporate lawyers.

As a result, some issues arise, such as code that is stuck on GPLv2 (e.g. removed the upgrade clause like the Linux kernel) may be incompatible with LGPLv3.

This blog tries to explain some of the issues. http://nmav.gnutls.org/2013/03/the-perils-of-lgplv3.html

I strongly disagree, since at a conceptual level it is a very simple license. As a distributor, you got provide users with the source code of the LGPLv3 parts and permit/provide so they can replace it with a modified version of their choice.

To make a car analogy, if the tires are made under LGPLv3, you got to tell them what kind of rubber it is made of and permit car owners to change the tire without the car saying "unapproved parts used, so I will refuse to start now until you have bought approved tires from an official car dealer". Every car made before 2000 managed to do this without even thinking about it.

FSF consider GPLv2 to be incompatible with this deal from a US-legal view, which is the same view that claim "further restrictions" only covers restrictions made from software licenses.

It's gone from (L)GPL v2 to v3, which some companies care a lot about (e.g. Apple).

Apple already refused to use LGPL v2 stuff. They refused to use anything (L)GPL in the past and now they continue to refuse to use anything (L)GPL. Apple is not a useful data point about what has changed, because they have not changed position based on v2 vs v3.