If you've been working at a big AAA game developer more than likely you've been using their proprietary engine. In my case I was working with Dunia which is a far deviated version of the CryTech engine. I've worked with this engine for almost 9 years. My role was to build and script game play areas and missions. I did not consider however that while I was working with Dunia the industry was changing.
Unreal 4 & Unity made game development so much more accessible for small startups which is was great! Big AAA publishers are really more of a money machine who's goal is to churn out cash rather than taking risks with innovative ideas. Giving these little studios access to make something new not only helped them, but it helped the industry as a whole. The competition forces AAA out of their comfort zones and drives the whole industry forward. So when the time came for me to move on I jumped out into the job market with 20+ years of game development experience expecting that I'd be in demand, but that was the wrong assumption.
Working for 8+ years with a proprietary engine translates to zero experience for most companies that use UE4 or Unity. They're not interested in dealing with anyone that would need to get up to speed with their production. They want someone that has been living with their engine daily for years. Sure, I've used UE4 and I can create a map and script it but this is not a major part of my portfolio. I've been building in Dunia and id Tech engines shipping titles like Farcry 5 but this is of no value to them. I had one developer straight up tell me, "My years of experience means nothing because it was with proprietary engines. I have no useful knowledge for UE4 / Unity devs." He went on to say, "You need to be using UE4 every day for 2 to 3 years min."
Let me be frank about this shortsightedness. Most game engines are similar. They all basically do the same thing. For a person to move from one to another does require some time to get up to speed. An experienced designer generally knows what they are looking for, they just need to learn where to find it in an unfamiliar engine environment. This would take two weeks, maybe three. After that you then have a designer that has shipped top selling AAA titles since before you even started in the business. Isn't that worth it? Are two weeks going to be such a setback? I shared this feedback with a friend and studio Creative Director he replied, "What a load of bullshit. That excludes so much of the industry workforce."
This attitude isn't just in regards to engine experience, its with platforms as well. People that have worked on PC or console titles are at a huge disadvantage if they're looking to change to mobile or VR development. Mobile studios aren't interested in console devs and vice versa. Even within familiar platforms if you've only worked on single play VS multiplayer or if you've never worked on a free-to-play game you're immediately less desirable. So what are these developers looking for? I think I've found the answer.
Right now the majority of studios don't seem to be looking for creative, experienced people to help improve their titles. They want someone who can quickly fill a seat and close some JIRA tasks. No thinking required or even desired.