I found this (replace the XXX's) as the #1 hit for a question. The answer seemed very "stack exchange" and indeed it was:
http://htmlasks_XXXXXXXXXXXXX.com/why_is_the_ubuntu_software_center_being_replaced_by_gnome_software_in_16_04
Why is the Ubuntu Software Center being replaced by GNOME Software?
Does SE patrol for such things: is there a reporting mechanism?