That's a problem of the companies. GPLv3 contains no fundamental changes in the freedoms it gives and requires to be uphold - it just clarifies some things explicitly (in particular that tivoization is explicitly forbidden, where before it was some legal gray area) and gives better compatibility between the GPL and other FOSS licenses.
You explicitly wrote about GPLv3 in your post above. For GPL software in general, your claim is surely true. But I see no reason why GPLv3 might make a difference (except for the few rare cases where tivoization might play a role) over GPLv2 here.
Given they were using the LGPL before, which means they were already using GPL software, it means they are already in conflict with their legal department.
It is a difference (also to the legal department) to use GPL/LGPL software (say, GNU/Linux) or develop (or even release publicly) software that uses components/libraries that are under GPL/LGPL. I think pjmlp was implicitly only talking about the second scenario.
