Since Baltimore City is getting more money per student, why aren't they able to properly maintain their buildings [1]? Poor management? Corruption? Lack of heating and working bathrooms is inexcusable.
That might be true generally (and cities like New York and DC have really high per capita spending for that reason), but Baltimore is quite a bit less expensive than the surrounding suburbs. You can buy a gorgeously renovated townhouse in a nice neighborhood for $400-500k, a fraction of what it would cost in Montgomery County.
How expensive would it be to put space heaters in every classroom? Even window heaters are only $500. Surely a school district that spends $17m a year on maintenance can come up with that. My guess is bureaucracy/mismanagement is the real problem. The larger a school district is, the more bureaucracy.
Suburban areas in the US aren't old enough to get hit with infrastructure maintenance costs like the urban areas are. This is a really interesting article about the profitability and maintainability of growth: https://www.strongtowns.org/the-growth-ponzi-scheme/
Baltimore has much older infrastructure and buildings than any of its suburbs. That would lead to higher costs not to mention higher costs for being an urban metro to begin with.