A crude precursor to the ideas in the Alto can be seen in the mother of all demos with Doug Engelbart imho.
After being exposed to PARC's self-congratulatory self-promotion for decades, Nelson's history is a breath of fresh air.
This is not to devalue what PARC accomplished, but that its accomplishments must be taken in perspective.
It All Went Wrong at Xerox PARC is also on YouTube: