Yeah they were probably the last great small Android phones. The “small” phones of today like the Zenfone and base Galaxy S series are noticeably larger.
EDIT: Just want to add that both the XZ1 Compact and the XZ2 Compact are still being maintained. The XZ1 Compact supports both iodéOS and LineageOS for microG, while the XZ2 Compact is an official LineageOS device. Obviously not a perfect solution for everyone but they are still viable if size is a key issue for you.