This is the fundamental reason the modern internet is centralizing to a couple of entities.
"This has to be one of the worst ideas since MS-DOS."
Yes, the modern browsers have taken us back at least 20 years when it comes to UI design, component based programming and distributed systems. The web is an endless stack of kludges, held together by duck-tape. I can back this up, in case you don't believe me.
But, we should ask ourselves how it became such a stack of kludges. And I think Alan hits the nail on the head.
"At the very least, every object should have a URL. I believe every object on the internet should have an IP. It represent much better what the actual abstracts are of the physical hardware to the bits. "
Beautiful insight. The URL does not scale from a systems perspective. In my designs, I see myself often using UUIDs and negotiation to transfer knowledge about entities. The URL (and RESTful communication) is an annoyance. It fixates the location to something arbitrary. I can only use one hierarchy to denote the same object. I cannot easily renegotiate how the same things are named in my systems. And, the worst: the type of the object is often included in the url. `https://foo.bar/person/123` fixes the type 'person' to the object 123.
URLs nowadays are an abomination. Most are not durable, contain excess information and suffer from projecting the information against an arbitrary axis.
Finally, all developers should at least once have implemented their own compiler. It is not a hard experience at all and can be done in around 100 hours by someone with a medium skill in programming using a good text-book. It gives a truly fundamental insight into systems design and should simply not be skipped.
W.r.t. tools: I assume any programmer worth his salt has build at least some of their tools! Perhaps I should start asking this at interviews. If you don't understand how your tools are built, how can you even begin thinking about building tools for others? And how can you understand, without attempting a crude build yourself? All the hard things are already done, the literature is there, the books are written.
So, anyways, you make a bold claim: "most of what he said was wrong." This is awfully vague, I am afraid. Lets make it a challenge. Except for him making predictions, I challenge you to come up with a couple of statements from Alan Kay, and we'll discuss it.