The popular open source licenses explicitly give permission for people to resell your work, it's not even buried in the small print or anything. e.g.
GPL: "Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for them if you wish)".
MIT License: "including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software".
Apache License: "each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as stated in this section) patent license to make, have made, use, offer to sell, sell, import, and otherwise transfer the Work".
This should no more cause burnout than someone buying your old car and using it for an endurance race makes you tired. Where there's burnout involved it's more likely the demands for support and fixes that head back upstream without any associated money. More concerning is Copilot trained on code which isn't GPL licensed or similar. Sharing code doesn't automatically grant anyone any license to use it for anything at all.