For centuries, the main educational resources were written texts on tablets, manuscripts or books. Now, educational resources are readily available under many types, whether physical or digital.
In the early 2000, the concept of learning object emerged.
Learning objects (LO) are defined as any entity, digital or non-digital, that may be used for learning, education or training.  So basically, it could be any object that help learner achieve one or more learning goals.
This broad definition is necessary because education is changing tremendously due to the combined effect of demographical and technological explosions over the last 70 years. 
New types of LO have recently appeared such as MOOCs or podcasts and new one will undoubtedly be created with the rise of Virtual reality and Metaverse.
Up to now, education was focused on scalability, i.e. how to provide satisfactory education at large scale. Going forward, education is aiming at providing a more personalised learning experience to each learner (e.g. adaptive learning).
The education is thus facing a paradox: how to deliver large scale education (i.e. standard learning pathway), while personalising each learner's learning pathway .
Learning object is a key part of the solution to this paradox: by breaking down the learning pathway in smaller objects, we can interchange the learning objects in a learning pathway, while making sure that they all lead to the same learning goals.
This shift is related to the concept of Competency-based education compared to Traditional education systems.