Kernel design is (to me) another one where ideas have flowed into other software fields - there were monolithic kernels, micro kernels, and hybrid kernels, and they all need to work with third party modules (drivers)

The lessons from all fields seem to be relearnt again and again in new fields :-)

Because learning how to make a proper one requires building your own broken one first.

It might be slightly sped up by reading up on theory and past experiences of others.

I am around mid life and I see how I can tell people stuff, I can point people to resources but they still won’t learn until they hit the problem themselves and put their mind into figuring it out.