No it's because XMPP's multi device semantics are the opposite of what you want, and they never got offline messaging and file sharing to work reliably across clients.
XMPP was created for and by geeks who roam from workstation to workstation, not people who need to preserve history and state while using multiple devices at the same time under spotty connectivity.
It has extensions like "Message carbons" and "Message archive management".
Google Allo is launched in late 2016 and it is strictly bound to single device. This is marketed as feature, because only geeks and rocket engineers use workstations, normies do internets on cellphone (and only terrorists and drug dealers have more than one cellphone).
XMPP was created for and by geeks who roam from workstation to workstation, not people who need to preserve history and state while using multiple devices at the same time under spotty connectivity.