I think there's a difference between the relevance of degrees and the concept of lifelong learning. We are unlikely to remember much of the minutiae in the material that we're taught during primary school and high school - for instance, I'd be hard pressed to remember quotes from Henry IV or the finer details of the French Revolution, but it's arguably taught us relevant skills that will be useful for employment or further education - such as in effective communication, teamwork (from group assignments), critical thinking or in the scientific method. Arugably, some of these skills might not be particularly well developed and taught in higher education (especially if employers/students aren't satisfied) but it's not necessarily the point of degrees for graduates to retain and apply all of the curricula in their work/research.
As to the concept of lifelong learning - I think it's something of a concept that students and graduates should recognise as a requirement for many professions. In health sciences for instance, continuing professional development is often required both informally (eg healthcare professionals keeping up with advances in medical science through journals and conferences) and formally (requirements for professional accreditation), and universities should develop curricula around this (such as encouraging students to develop skills in critically appraising research papers for STEM courses, or providing placement/internship opportunities)