I've watched bounty and grants programs for decentralized systems for over 3 years consistently fail to produce real results. The product of bounties has almost universally been bare-minimum POCs to satisfy the requirements followed by complete abandonment of the result because ongoing ownership wasn't planned for.

Bounties have been really successful in the security space because the terms are clearly defined and there is zero ongoing effort required after the bounty is claimed. Something more sophisticated is needed to build complex systems.