This feels eerily close to having someone try to convince me to be join their religion. You don't need to force your opinions into others. Let them choose. If folks agree then the license will hold them back in terms of building a community. There are plenty of great open source kernels that don't use GPL, including freebsd. I think most embedded os kernels are not gpl (zephyr, freertos, etc). I would argue that Linux does well in spite of its license not because of it.