The boost169 package is intended to be a compatibility package only, not meant to replace the regular boost package. Indeed, the RedHat-core boost package (e.g., in version 1.69 on Fedora 30 and 31) is already available on Fedora distributions.
A few prokects (e.g., k3b) will still need Boost Python2 sub-packages for a while. See https://bugzilla.redhat.com/show_bug.cgi?id=1767503 for details and references.