Just read all my posts again and then you will realise that you constructed a strawman argument and addressed a point I never said. No-one directly said that beginners should be contributing to the Linux kernel when I actually said that beginners should get experience from joining other similar but easier open-source OS projects before joining a company specialising in Linux development to be long term Linux contributors.
Technically, anyone can contribute to the Linux kernel due to its open-source nature given that their patches are reviewed by the maintainers and it is then accepted.
> Why should kernel devs (paid by companies) spend resources on making it easy for beginners?
Not only I didn't say that, but you do realise that there are companies that exist who both contribute to the Linux kernel and offer training for a one time fee as an introduction into kernel development? Given the beginner meets the experience pre-requisites: Bootlin, BayLibre and several others have professional kernel contributors that do this.
> If you want people to get into kernel development, there are kernels wrote specifically for teaching purposes.
Read all my posts again. I go beyond just 'kernels' and named other complete OSes to get OS development and kernel experience from before joining a company specialising in Linux development. I said in the last post that '...the starting path is certainly not Linux.', it seems you certainly didn't read that.
Every professional Linux kernel developer started as a beginner somewhere and certainly wasn't born an expert. Some beginners were university students who either joined Linux companies by participating in programs like Google Summer of Code or took a paid Linux kernel training course by a company specialising in kernel development. You will notice that your last comment is in agreement with my whole argument.