Built for the climate of the past? Which one, the one over thousands of years in which CA routinely undergoes multi-decade droughts, or the more recent one of a

Built for the climate of the past? Which one, the one over thousands of years in which CA routinely undergoes multi-decade droughts, or the more recent one of a few hundred years in which the dry periods last just a few years? I think the problem is the people of CA are not willing to engineer water infrastructure necessary to support the population based on the longterm climate record.