https://www.cbpp.org/research/state-budget-and-tax/most-stat... The question is not really is it increasing — but how much it has increased and whether that actually affords a quality education. https://www.theguardian.com/us-news/2018/sep/07/us-education...
(Hint: it probably has to do with the fact teaching makes very little $ in most places and is not treated as a good career in the states)
FTFY
https://www.aaastateofplay.com/school-districts-ranked-by-th...
Especially in inner cities, many of the better performing school districts spend far less than the places serving poor communities. Camden NJ is one of the highest spenders, so are a lot of city schools in Illinois. Famously "good" schools, like Stuyvesant which spends about $17,000 per student, don't even make the list. It's far below the average for NY!
This is so provably false that I'm amazed anyone could have this opinion. The US spends huge amounts on education. More than almost any country. Neither education spending nor property taxes have declined.
Government current expenditures: Education
https://fred.stlouisfed.org/series/G160291A027NBEA
Personal Current Tax Receipts: State and Local Government: Property Taxes
https://fred.stlouisfed.org/series/S210400
US education spending is one of the highest in the world, and is also increasing 2010-2019 faster than almost any country:
https://nces.ed.gov/programs/coe/indicator/cmd/education-exp...