It seems that later in life he quit focusing on computer science, and may have been out of touch with it as early as the start of the 70's. Here's his obituary

It seems that later in life he quit focusing on computer science, and may have been out of touch with it as early as the start of the 70's. Here's his obituary: https://www.theguardian.com/technology/2009/sep/22/peter-landin-obituary https://www.theguardian.com/technology/2009/sep/22/peter-lan... "Always bisexual, he threw himself into the politics of the Gay Liberation Front in the early 1970s. He separated amicably from his wife in 1973, and was closely in touch with her and his children till his death. For the rest of his life he pursued gay politics, and his house in Rona Road, Camden, became a gay commune. Always more of a facilitator than an activist, he saw many plots hatched at his dinner parties. Aids: the Musical! was conceived there, as was the reinvigoration of Gay Pride marches in the mid-80s, just in time for the battle over Clause 28. Towards the end of his life, Peter became convinced that computing had been a bad idea, giving support to profit-taking corporate interests and a surveillance state, and that he had wasted his energies in promoting it. But whether he liked it or not, his ideas underpin developments to this day."