Accessibility tools often thrive as open source precisely because they can be adapted to diverse needs, audited for security, and maintained by communities when individual developers move on.
I see software thrive much better when it's sold for a fair price by a solo developer or small shop. Boutique software is great for users and great for the programmers. And if the OP has no monetary interest, he/she could give away the software for free while keeping the source code for themselves.