There is a fatalism mentality when it comes to writing about big technology ambitions like this. Maybe people are just jaded and used to being let down so much. There is zero doubt in my mind that this endeavor will cost more than expected, take longer than expected, etc... but at the end of the day the effort alone is going to spur other tunneling companies to push for innovations as well. Who knows if any of these early prototypes prove useful, but it sure is clear that Elon sees a lot of room for improvement in the technology, and at this point I wouldn't bet against that.