It seems to me that there may be room for disruption. Currently every TBM (tunnel boring machine) is completely bespoke and is used for exactly one project and is then dismantled/recycled. They cost hundreds of millions of dollars each. I imagine there are relatively few manufacturers out there building TBMs.

Actually in some ways it bears a resemblance to the spaceflight industry (expensive, custom-made, few players). Coincidence?