Any large project is likely to have difficulties of some sort that need to be taken into account to overcome: it's the nature of the beast. You're right, these are valid concerns. Asking the questions as your parent does implies that those at the Boring Company—while they may have not solved them in all cases—are not aware of them, especially as these aren't new problems. I speculate that the downvotes are a reflection that your parent isn't granting them this benefit of the doubt. One can infer from the FAQ that they are thinking of this in part from the R&D bullet point:
> Tunneling R&D. In the United States, there is virtually no investment in tunneling Research and Development (and in many other forms of construction). Thus, the construction industry is one of the only sectors in our economy that has not improved its productivity in the last 50 years.
> Tunneling R&D. In the United States, there is virtually no investment in tunneling Research and Development (and in many other forms of construction). Thus, the construction industry is one of the only sectors in our economy that has not improved its productivity in the last 50 years.