The real way a senior engineer trains juniors is by selecting appropriate work. They thread the needle of a number of factors: it needs to be done, its within reach, will build their skills, will educate them on product/business/process, they will find rewarding, will give ownership, relevant staff can support them etc. These factors are so important that the senior engineer might need to negotiate with the product manager to bring appropriate work forward to avoid failure or killing the enthusiasm of the junior.

What can't really happen is for a junior to suggest work. The experience and context they lack is for the business, the user and the strategy. The junior's biases for what they think matters are usually much worse that the senior's for what works e.g. they want to improve cosmetic factors or add cool features. Its not that they are wrong, the product might be offensively ugly and the cool features might be game changers, but professional development is a parade of gut wrenching compromises because the constraint is time and resources not imagination and ambition.

That said, I agree with the thrust of the article - the risk of senior engineers "fighting the last war" and accruing a set of limiting beliefs is very real and the naive optimism of a junior challenging them is part of the value they bring.