“More concentrated on higher-income earners” is both more accurate, and more relevant to the effect of the SALT limit (though having higher average income is also relevant to the SALT limit, overall tax burden and distribution across the income spectrum aside.)
E.g., R-trifecta Iowa has a higher overall tax burden than D-trifecta California, but substantially lower high-end taxes. [0][1]
[0] https://wallethub.com/edu/states-with-highest-lowest-tax-bur...
[1] actual total state & local tax burden by income is hard to find, but top income tax rates are indicative here: https://turbotax.intuit.com/tax-tips/fun-facts/states-with-t...