Patent applications have fees.

Prototypes cost money to build.

Manufacturing requires equipment and facilities.

Marketing requires investment.

The capital markets of mid-twentieth century America were largely closed to Black Americans, both formally through discriminatory lending practices and informally through the social and professional networks through which investment capital actually flowed.

Black Americans built their own financial institutions — banks, insurance companies, investment firms — specifically to address this gap.

But these institutions, operating in a segregated economy, were necessarily smaller than their white counterparts and had less capital to deploy.