It really depends on the target and the quality of the vulnerability. For example, low-quality software on GitHub might not warrant high bug bounties, and that's understandable. However, critical components like KVM, ESXi, WebKit, etc., need to be taken much more seriously.

For vendor-specific software, the responsibility to pay should fall on the vendor. When it comes to open-source software, a foundation funded by the vendors who rely on it for core productivity would be ideal.

For high-quality vulnerabilities, especially those that can demonstrate exploitability without any prerequisites (e.g., zero-click remote jailbreaks), the bounties should be on par with those offered at competitions like Pwn2Own. :)