It begins as a regional cost issue, which any drop in enrollment makes untenable.  

To set the baseline:  Districts across the state have found that the high marginal funding from LCFF's concentration grant is a two-edged sword. (Effectively, every district is compensated about $8,000 per student as a base grant.  If a student is low-income or an English learner or a foster youth, the district receives an additional $1,600 in supplemental compensation.  If more than 55% of the students in a district receive the $1600 supplemental compensation, then the district receives an additional $4,800 per student after that first 55%.) It has been a wonderful boost for districts with over 55% low-income/English-learner child (LI/EL) (“unduplicated”) headcount, which have a unique challenge in addressing the needs of a predominantly disadvantaged student body.  However, any district over 55% unduplicated finds that the loss of a single LI/EL child reduces district funding by a noticeable $14,400. This adds to the frustration with charter schools, especially when they (a) attract unduplicated headcount, but disproportionately leave very-high-cost special education students in the district; (b) are entitled to facilities whose overhead cost must be absorbed by the district; and (c) leave the district with a preponderance of highly-challenging-to-educate population of itinerant students (whose parents cannot take advantage of lottery-selective charters).   

In high-regional cost areas, this pain is four-fold:  

• First, every resource has already been already been stretched to accommodate regional costs.  There simply aren’t the maintenance deferrals or experimental program cuts that can absorb a cut, the way there are elsewhere.  
• Second, a false gentrification often replaces a $14,400/year child with an $8,000 a year child.  Nominally, a cut in special services should occur — but, in the high regional cost areas, the incoming children may be just as disadvantaged as the ones they’re replacing.  The Federal income level used to designate Low Income students is fixed across the state. In high regional cost areas, 75% of that level is required for housing alone — vs. 33% elsewhere — based on HUD Section 8 data.  Indeed, a child may be reclassified simply because his parents’ income goes up $5,000 a year … while their housing costs climb $6,000.
• Third, in high-cost areas, a higher-proportion of children attends private schools — but not children with special needs.  They attend public schools for special education services, furthermore, their parents are usually very good at advocating for accommodations.  So there is already a special-needs concentration, which is further exacerbated when the movement to charters increases it.
• Finally, teacher retirement is generally helpful to budgets as older teachers at the top of the step-and-column pay scale leave and new ones, at the bottom of it, join.  But, in high cost-of-living regions, those who are leaving generally are homeowners with low mortgage and property tax costs, while newcomers are competing for housing in a hot economy.  Districts in these areas are now trying to get into the housing business to mitigate this — with attendant costs and diversion from a focus on education children.