https://www.northjersey.com/story/opinion/2021/05/17/salt-de...
NJ has very high property tax rates and high home values
NJ income tax is ~4%, and average property taxes are not that high:
https://www.nj.com/politics/2020/03/njs-average-property-tax...
It would be nice to find statistics by percentile, but I would find it hard to believe that many single households are living in houses paying $8k+ property tax, and married households are paying $16k in property tax.
I use $8k and $16k because that would mean the remaining $4k and $8k would be for income tax for a person earning $100k/year (78th percentile) or a couple earning $200k per year (83rd percentile).
https://dqydj.com/income-percentile-by-state-calculator/
Edit: the best way to figure out if the SALT caps hurt or not is to see if the amount of people itemizing on federal returns increased or not. I cannot find any NJ specific statistics, but IRS says only 11% of tax filers itemized in 2019.
I would bet on school closings and the trend of higher taxes/less government services, but the latter is unavoidable due to the outlier amounts of debt NJ has.