Industry generally doesn't care after your first job (at your first job, school is the only thing to go on). People put their GPA because they think it looks good. It certainly can and does impress people, but always looks a tad boastful and silly (but don't be too dissuaded if you have a great GPA, because this is a scenario where you need to sell yourself and boast). Schools often can't even easily access the transcripts of people who graduated more than 15 years ago; they only rarely get requested.
Like everyone else, industry does care that your degree is real, but that is often done via a separate verification process that is easier and separate from transcripts. Many will take an official transcript as proof (and many others will take an unofficial one).
Postdocs are a different story. In academia the transcript is obviously much more valued for rating people. Though it's often completely up the the prof doing the hiring. At the official school level, they are mainly interested in verifying your degree in order to give a postdoc title.
By the way, probably the biggest reason GPA's at the doctoral level are ignored is essentially grade inflation. At research schools, many grad classes just give everyone an "A" for showing up. Or even difficult classes will curve everyone to only "A"'s and "B"'s. Because even a mediocre GPA at the grad level can lead to dismissal. Doctoral students are assessed in other ways instead.