The next Xbox, Project Helix, could theoretically have the largest library of any home console. Not only will it play PC games, we now know, courtesy of a leaked memo obtained by The Verge’s Tom Warren, that it will run games from every generation of Xbox: the original 2001 Xbox, the 2005 Xbox 360, the 2013 Xbox One, and the 2020 Xbox Series, as well as any new Helix titles.

We already knew that Microsoft was bringing a limited sample of original Xbox games to PC, and we already knew it was prepping a way to digitize your Xbox One and Xbox Series discs. The leak fills in the missing puzzle pieces.

Microsoft is bringing Xbox 360 games to PC, too, and explicitly states that those games will run on Helix in addition to “Xbox PCs.” The document also clearly states that your digitized Xbox One and Xbox Series discs can follow you to “any Xbox device,” so Helix will get those too. Five generations of Xbox games under one roof.

But before you get too excited about “backwards compatibility,” you should know this isn’t the same as sticking a PS4 disc in your PS5 (or a Switch cartridge in your Switch 2) and pressing play.

First, Helix may not have a disc drive at all. Last we heard, Microsoft is still deciding that.

Second, it appears that these forms of backwards compatibility are at the mercy of game publishers. The leaked memo is Microsoft trying to convince those publishers by dangling profit in front of their eyes.

The memo is literally addressed to publishers, and it’s transparently a sales pitch. One section is titled “Why publishers win.” Spoiler: publishers primarily win because they can sell old games like they’re new again.

Even with the disc-to-digital where publishers presumably don’t get a new sale, Microsoft offers a carrot: “Turn physical disc owners into digital customers” is the company’s sales pitch there. Maybe Johnny won’t buy a new copy of Mass Effect from you, EA, but perhaps he’ll buy five future games digitally!

Don’t get me wrong, it’s good that Microsoft has carrots to dangle here. Because it sounds like the Xbox maker can’t even convert Xbox discs to digital without that publisher buy-in.

Though Microsoft says publishers don’t need to lift a finger to make disc-to-digital work — “Publisher action: none required,” it writes. Microsoft says early on that both of its new game preservation programs require opt-in.

With original Xbox and Xbox 360 games, Microsoft is even more explicit: publishers will have to give their permission for each and every title, decide how much they should cost, and decide whether those games should be included in an Xbox Game Pass subscription or only available for standalone purchase.

It’s not surprising that Microsoft would need permission. When Nvidia’s GeForce Now cloud gaming service tried to let you stream even your own already purchased PC games without permission, it got in trouble with lots of publishers and eventually went opt-in.

But GeForce Now also shows how you can’t rely on those opt-in permissions to stick. Some will disappear when publishers later revoke that permission or other rights issues creep up, and some publishers won’t opt-in certain games to begin with.

At least Microsoft is a giant game publisher itself, even if it has fewer studios after its big Xbox “reset” that’s putting thousands of employees out of work.

But even Microsoft may only have so much appetite to make old games run like new when it has to do all the work itself. Microsoft made roughly a quarter of the Xbox 360 library and around 6 percent of the original Xbox library play on Xbox One and Xbox Series consoles between 2015 and 2021, but that’s as far as it got.

Also, Microsoft ownership is no guarantee a digital copy will remain available for purchase: multiple Forza Horizon games have been delisted, including the backwards compatibility version of the original game, because their developer only secured temporary licenses to content inside — licensed cars and licensed music rights can expire.

I hope it works, because it sounds very cool — Xbox 360 games with cloud saves, starting as soon as 2027! — and because the Xbox and PlayStation will badly need to justify their price tags in the age of RAMageddon and in the post-disc era. But what would make these competing platforms great?

With Sony, I think the answer is handheld. With Microsoft, maybe we’ll get one Xbox to play them all, but only if the publishers can be convinced.