The challenge is that to design a new line, or production cell, or process they need a broad range of expertise that is very specialized. For example, they may need folks that are phds/experts in plasma deposition/sputtering/etc. to do a bunch of multiphysics computer simulations to get the operation in the chamber right. Then they need folks with expertise in building the chambers, and associated cryo pumps, then they need robotics experts to architect, design and implement all the automation, chemical engineers for all the crazy chemistry going on, etc. It would be very expensive to keep all those folks on staff, and even harder to keep them all busy.
I view it like the construction industry. I worked as a concrete/asphalt inspector for my local municipality in college and the cycles of the road repair industry are similar in my mind. In this world there are lots of "crews" that travel around the country following the work. They start in the south in the winter, and gradually work their way up to the north as the ground thaws and road construction can be done. They usually have a 2 week - 2 month contract in each town and then move on. No one area has enough work to keep them busy for a season. The industry is built on that ability to maximize work/profit and minimize downtime by moving from customer to customer as the work does also.
I view it as similar for many of us who do/have worked in semi. When there is a glut of work, it's all good. When there isn't there are hundreds or thousands of highly skilled, highly specialized folks needing work. Those folks/consultancies typically are able to pivot to other industries that need the same skillets readily and easily (like medtech, aerospace, automotive, etc.) and keep working during the slow period for semi. The alternative would be for semi equipment designers/manufacturers (like ASML, etc) to rely more on in house permanent workforces and less on contractors and subcontractors but I fear a fundamental change like that may not be sustainable from a cost standpoint. These companies already have huge swings in their workforce numbers every few years, often hiring or letting go hundreds or thousands at a time.
Edited - typo