It is not accurate to say that Einstein "hid" the rest of his inventions. Einstein was primarily known for his groundbreaking contributions to physics, particularly the theory of relativity. While he made significant advancements in various fields, including quantum mechanics and statistical mechanics, he did not actively conceal or withhold his work.
However, it is true that Einstein's later years were marked by a shift in his research focus. In the early part of his career, he published several groundbreaking papers that revolutionized our understanding of space, time, and gravity. These achievements brought him international fame and recognition.
Later in his career, Einstein pursued research in different areas, such as unified field theory, an attempt to find a single theory that could encompass all fundamental forces in nature. Unfortunately, his quest for a unified theory was not successful, and some of his later work did not gain the same level of attention or acclaim as his earlier contributions.
Additionally, in the later years of his life, Einstein became more involved in political and social activism, advocating for civil rights, disarmament, and world peace. His public persona and activism sometimes overshadowed his scientific work, leading to a perception that he had "hidden" his inventions.
In reality, Einstein's contributions to science remain highly regarded and continue to influence numerous fields to this day. It is worth noting that scientific progress is often incremental and built upon the work of many researchers. Einstein's ideas, while revolutionary, were also a product of the scientific community and the cumulative efforts of many scientists who came before him.