Not parent, but the cause is obvious to everybody in the field: existing fundamental theory (general relativity from 1915 and Standard Model, completed by the m

Not parent, but the cause is obvious to everybody in the field: existing fundamental theory (general relativity from 1915 and Standard Model, completed by the mid-70s) while manifestly incomplete, is consistent with all available experimental data. New accelerator experiments capable of pushing significantly beyond the explored energy range would take a decade+ to build and cost tens of billions (and up), and there is no guarantee that they would find anything new.