I think that a lot of companies stepped back from the GPL when GPLv3 was announced, because it puts some pretty severe restrictions on how you can productize.

The tl;dr is that for any GPLv3 software that you ship, you have to also give your users a way to install a modified copy. If you're trying to ship a secured product, that basically means that you have to give code/rootfs signing keys to your customers. This is a non-starter for many kinds of products that need tamper protection (whether for product, legal, or safety reasons).

The Linux kernel remains on GPLv2, and is still used quite heavily. Most GNU software (coreutils, gcc, etc) moved to GPLv3 and then commercial companies abandoned them in favor of permissively-licensed replacements.