Innovating on the TBMs is definitely part of it; I don't know why you are concluding from a picture that it isn't? Boring smaller tunnels is also part of it.

You can read more here: https://www.boringcompany.com/faq/

I don't have an easy way to check your claims against Elon's, for example whether existing "modern" TBMs are fully electric as you claim, or run on fuel as Elon claims, and whether continuous tunneling is the norm or not.