It would be possible if the interest were there, to have several ski
tunnels built in the US. The expense of construction and maintenance
would be born by the tourists and athletes who pay to use the facility.
Less expensive, the artificial ski track material could be set up at
universities with ski teams who would allow public use to offset costs.
Up to now, no entrepeneur or consortium of interested investors has
been interested enough to devote start up capital and logistics studies
to building a ski tunnel. If the good citizens of the US of A became
cross-country ski fanatics, or at the very least more interested in
nordic skiing than they are presently, then a ski tunnel might become
reality. I won't hold my breath.