Title of that article: "NJ 4th Graders Score Low on Literacy, Still Ahead of Nation"
Throwing more money at the problem often makes some progress, but it's not always a definitive solution. Tough problems usually involve reorganizing processes, which tends to be harder than spending more money or recruiting more talented people.
It doesn't help that teaching programs in universities hold anti-science views about reading and reading comprehension and still cling to whole language nonsense. Furthermore they often reject broad cultural knowledge and vocabulary as key components of reading comprehension and insist that (despite evidence to the contrary) that it is a discrete skill that can be built in a vacuum.
Not being proficient does not mean they can't read, it's more that they're not "good" at reading. The same article says that the national numbers are even worse. The article only states that the gap between low income and wealthier students increased by 3% but it's not clear what the actual total difference is. If you look at the underlying data[1] you'll see that the national average is actually below proficient and that New Jersey is consistently above average, regardless of income. Certainly there is a difference in proficiency by income but there are far more factors at play there, most importantly the child's home life.
A hypothesis- their school reading lessons aren't being reinforced at home. Maybe their parents are too busy to do that reinforcement, working long hours, etc. Or there's a housing stability issue that lower income families often encounter.
How are the other 22% of low income fourth graders able to read?
[0]https://acnj.org/newsroom/news-releases/nj-4th-graders-score...