Agree, but over the last two Papacies ecumenical services with Popes in attendance have happened both in Rome, (Benedict and Rowan Williams,  then Francis and Justin Welby)  and at Westminster Abbey (Benedict) and Canterbury (John Paul II). The more interesting development has been pure Anglican services of evensong at two Roman basilicas, including St. Peter's.  For the record, an Anglican cathedral in England hosted, a few years ago, an RC traditionalist group celebrating the Latin mass at the altar, and Canterbury hosted the regular RC mass but eastward facing.

The recent installation service was a continuation of a process as you know but readers may not, and not something new.