Here we go...
None of the major Western defence manufacturing firms hire ex-military guys to do graphic design, copywriting, video creation, digital campaigns, designing pavilions, creating brochures, web design, and so on. I've been to multiple defence exhibitions and can tell you that the senior sales reps at LM, Boeing, Dassault, BAE, General Dynamics, etc, are also professional salespeople who've worked 10-15+ years at Microsoft, Dell, GE, BP, Shell, etc and not ex-military guys or serving military guys.
Actually, I do know who runs the media campaigns for the PAF. However, I also know that 100% of the marketing output isn't their fault because, at the end of the day, the people above them don't understand marketing enough to let them do a good job.
I'll give you a story from a past marketing person at the PAF. This person advised AHQ to contract a professional video team and some time on the C-130 or CN235 to take aerial footage of the F-16 and JF-17. AHQ said no. Then, some months later, AHQ let a Chinese team do exactly that thing and the result was the following:
This is how we treat competent people from within the armed forces. No surprise. Again, we can't even sell our own salt without India claiming it's theirs, the rest doesn't surprise me. The fact that the marketing work didn't go to a professional team was a bad decision. Full stop.
As to your first paragraph, the military does use private vendors. The product is as good as you can get from Pakistan. Obviously you cannot compare it to what is done by companies and countries with far more resources. Tenders for these services are open. If you and your people think you can do a better job. Please compete for the tender and don’t just complain.