Between laser printers and photo copiers (built on laser printer tech) Xerox did just fine.
If anything, Xerox's "willingness" (intentional or not) to allow the root ideas to grow in various places has been a blessing to the IT industry as a whole.
What you are suggesting is they could, or should, have become all the companies you listed. But that would gave been both impossible, and counter productive.
Steve jobs saw the GUI, and Ethernet, and object orientated programming, and laser printers, and office software, and yet Mac is famous for just the GUI. Others would run with networking, programming, MS with office and do on.
And in addition to those major players there were lots of others competing too.
So no I don't think Xerox management needs to be embarrassed. They saw the value printing and ran with that. They left others to develop the other ideas. And in the long run we are much richer for that.
So, from me anyway, there's no shame on them, rather a tip of the hat, and a nod to the vision they had to create PARC in the first place. They are the giants on whose shoulders we stand.