Not quite: have a look at these charts [0]. I believe that such a massive disparity in arrest rates between blacks and whites cannot be explained just by economic factors.

[0] https://www.washingtonpost.com/news/wonk/wp/2013/06/04/the-b...

Marijuana arrests account for 0.7% of the prison population.

It would be interesting to see the figures for other types of arrest.

Here is a study you might find interesting to add to yours

https://www.prisonpolicy.org/reports/income.html