I think this a non-issue. Only problem was my assumption on the plugin provider installation mechanism.
After installing VirturalBox using my host platform software installer (dnf in my case) the command to start the VM succeeded.
.....
.....
Installed:
VirtualBox-6.0.14-1.fc30.x86_64 akmods-0.5.6-20.fc30.noarch
elfutils-libelf-devel-0.177-1.fc30.x86_64 kmodtool-1-34.fc30.noarch
akmod-VirtualBox-6.0.14-1.fc30.x86_64 VirtualBox-kmodsrc-6.0.14-1.fc30.noarch
VirtualBox-server-6.0.14-1.fc30.x86_64
Complete!
$ vagrant up
Bringing machine 'testinventory1' up with 'virtualbox' provider...
==> testinventory1: Importing base box 'geerlingguy/ubuntu1404'...
==> testinventory1: Matching MAC address for NAT networking...
==> testinventory1: Checking if box 'geerlingguy/ubuntu1404' version '1.2.12' is up to date...
==> testinventory1: Setting the name of the VM: tmp_testinventory1_1571664664932_17595
==> testinventory1: Clearing any previously set network interfaces...
==> testinventory1: Preparing network interfaces based on configuration...
testinventory1: Adapter 1: nat
testinventory1: Adapter 2: hostonly
==> testinventory1: Forwarding ports...
testinventory1: 22 (guest) => 2222 (host) (adapter 1)
==> testinventory1: Running 'pre-boot' VM customizations...
==> testinventory1: Booting VM...
==> testinventory1: Waiting for machine to boot. This may take a few minutes...
testinventory1: SSH address:
127.0.0.1:2222 testinventory1: SSH username: vagrant
testinventory1: SSH auth method: private key
==> testinventory1: Machine booted and ready!
==> testinventory1: Checking for guest additions in VM...
==> testinventory1: Setting hostname...
==> testinventory1: Configuring and enabling network interfaces...
==> testinventory1: Mounting shared folders...
testinventory1: /vagrant => /tmp
$