Heres my take on it....
Hardware was done last year.. Honeycomb availablity delayed the launch.
Xoom is launching only 2 weeks after Honeycomb Final was provided to them by Google.
Xoom 4G modem hardware finalized a month ago but all Xooms have 3G cards anticipating a 2010 release so rather delay the launch.. ship and sell all devices with 3G.. let some more 4G cities lite up.. offer a free upgrade in a couple months then offer 4G standard in all newly built devices.
Adobe 10.1 player doesnt work on pre release honeycomb xoom software versions.. ( I have one) Yes, while it is in the market.. it doesnt install at least on mine.
Adobe controls the availablity of their Flash Player.. not google, not motorola. I think they were trying to make the aggressive launch but since Honeycomb final is only 2 weeks old, there is some internal testing that has to happen before its certified.. most likely why the Playbook isnt out yet either.. flash player is not final yet...
This is my opinion based on the info available to me..
Mad