That's also true, at least to some extent. You just have to maximise your transferable skill set. In my case it worked out well. Petroleum work is roughly divided into upstream, mid and downstream sectors and each tends to run in economic cycles. When oil is cheap, upstream work drops, but refinery and chemicals boom. Other industries like cheap oil too, so pulp and paper and mining work increases. Pipelines move the stuff all the time and the bulk of that work is civil, heavily combined with the ability to coordinate diverse work groups. Being able to do something useful in each, I almost always had more work than I wanted.
After a few years of doing the details, it usually turns out better in the long run to start supervising and project management and leave the finite element and CFD stuff to the kids. Let them work the simulators, keep them pointed in the right direction, correct their mistakes and push out practical designs, on time and sometimes even under budget.
And having broad experience and knowing how to use it turned out to be my most valuable asset, IMO, at least for projects that involve multiple disciplines and coordinating numerous and diverse organizations. You can always sub out complex design to vendors and specialist engineering companies. Never get caught out "Not seeing the forest for the trees".