The fab itself, for example, you can't just setup a Twinscan in your garage. Even the floors are marvels of engineering. Culture is another subtle but huge factor. When chasing nanometers the fab becomes sensitive to things like deodorant and cigarette smoke. You can of course mitigate these issues, but having an aligned and motivated work force makes it easier.
I understand that this is a sensitive process but so is surgery which robots are able to do with remote control.
Manufacturing is a game of yields and margins. When you have thousands of operations and inputs, small changes have big effects. TSMC and Intel both have access to the same machines, it's what they're doing with them that differs.
Robot surgery is tolerant of a much greater length scale of defect than a modern IC chip and is orders of magnitude fewer process steps.
Try to watch a youtube video or something but even then you won’t see the full picture. There are so many layers and the wafer passes through different flavors of the same processes over and over.