The size of that intersection. And the need to at some point interface to the rest of the world, including the EDA world. Unless you build your own products fr

The size of that intersection. And the need to at some point interface to the rest of the world, including the EDA world. Unless you build your own products from system to physical chips in house (have your own fab) sooner or later you will need to interact, exchange source code or netlists in some form. Fabs expect you to use certain (golden) tools before accepting a design for manufacturing.