The story behind 1963, Alan Moore's tribute/commentary on Silver Age Marvel is a messy one. Back in 2010 Steve Bissette revealed that attempts to properly complete the series (with an annual to be drawn by Jim Lee) and/or collect what was published had failed:
He also stated that attempts to reprint and conclude the 1963 series have repeatedly failed over the last ten years, the most recent at Dynamite seemed almost to come to fruition, but did not, Alan Moore removing his blessing.
An Alex Ross illustration (now removed) would have formed the basis for the cover to the Dynamite hardcover.
As a result, it's been decided that a reprint will never happen. And copyright in the 1963 characters has been divided – Bissette's share forming the basis of his Tales Of The Uncanny project, now being published by About Comics, he's pulled copies of 1963 from his online store and he will no longer mention 1963 again.
When asked for comment, Rick Vietch told me "Nothing to add to Steve's statement except that I've instructed my immediate friends and family to pick up a baseball bat and bean me if I mention the idea of collecting 1963 ever again" and Nick Barrucci of Dynamite gave a similar "It's a situation that I feel is unfair to comment on. I respect all the creators involved, and somethings are best left not discussed in public."
And, in 2013, Bissette threw the towel in:
And as of January 2012, Alan made it abundantly clear nothing will ever be done with them, either, on his watch—so, party's over on that trio of works.
It sucks for our creative partners—Dave Gibbons, John Totleben, Chester Brown, and the colorists (Anthony Tollin) and respective letterers—and I'd be gobsmacked if Rick and Alan ever did anything with their part of it all, but that's their business, no longer any of mine (except where my clutch of properties come into play, which ipso facto defuses anything happening). If they ever do, nobody will be happier than me about it; no sour grapes there.
You see, I can't even really "license" those stories, much less issue a Creative Commons license—hence, my decision to announce anyone interested in doing so now has my blessings, as long as my © and ™ is applied, per our 1998 contractual agreement regarding the respective characters and two titles I do fully own.
There are a number of projects to create some kind of spin-off using the characters various artists own, most recently Don Simpson's 2023 announcement that he was creating a 1963 Annual. This is available to buy.
So, long story short (and ignoring the various recriminations), the only way you can read the comics is by buying the individual issues (as I did) or... the Internet Archive has them (for now).