TL;DR - Many times the cost of the LHC and unlike the LHC, the gains are likely to be incremental instead of revolutionary. The same funding could do much more good elsewhere.
To your point, agreed that even small, incremental gains for science are more valuable than what we are likely to get from AI.
Not really my area of expertise, but this article lays out her perspective on this for anyone who isn’t aware: https://www.scientificamerican.com/article/the-world-doesnt-need-a-new-gigantic-particle-collider/
TL;DR - Many times the cost of the LHC and unlike the LHC, the gains are likely to be incremental instead of revolutionary. The same funding could do much more good elsewhere.
To your point, agreed that even small, incremental gains for science are more valuable than what we are likely to get from AI.