I think that this idea might benefit from being parts of adventures rather than a complete adventure on a page. Even AAW Games' mini dungeons are two pages: half a page is a 32x20 (or 64x40) map; 1/4 page art; the rest is text.
For a "one page adventure"? I think a complete adventure on one page may be a bit too much chopped if it is an adventure in the traditional sense (setup, map, NPCs with motivations, adventure hook, etc.). If you are basing it on Grant Howitt's work (such as Honey Heist, working link here
http://lookrobot.co.uk/games/), then I would see it one way to do it as a series of adventures "themes" rather than a full mini adventure. They could start with a short intro followed by a bunch of rollable tables that skip most of the filler words. A heist adventure would start with a short intro that said the party is going to undertake a heist followed by rollable tables including who is the target (bank, casino, hotel, noble, rich person, etc.), employer (owner, competitor, spurned lover, etc.), item (money, jewelry, antique, magic item, land deed, etc.), complication (betrayal, traps, bad intel, unscheduled guard change, etc.), and so on. This would allow a customer to flip through their book of one page adventure themes for the scenario their players have put them in and quickly generate something that they can run with.
Something like this might violate the "one session" restriction, although there isn't a clear definition of what a session is in terms of time (which can vary widely by group). Is it 2 hours, 4 hours, or something else?
I think theater of the mind is likely the way to go, foregoing the map, but a small map can show more than including lots of "this room is 20 feet square with doors to the east and west". I think you might be selling yourself short on the one-page restriction for a practical reason: printing to place in a binder. Unless someone plans out a print job and stitches pages together, they are not going to be using the back of pages. This isn't the biggest problem ever, but that is a lot of wasted space in a binder. The second page gives space for a map. The second wall I can see a one-page-adventure author running up against would be the number of NPC stat blocks, spells, magic items, traps, and the like that would have to be included by reference
I think the one page format could work beyond adventures. Generators for city types (seaside town, mountain village, big city district), pubs (name, drink specialty, size, quality), and even encounters (themed, with a minimum party level, and multiple different creatures to choose from, showing how many to include per PC), or magic items. And not everything needs to be generators. A one page magic item that grows with the PC, has adventure hooks, and other features would be quite interesting. The supplements could come with built in organization; supplements could be numbered by Type(Chapter).ItemNumber. A Table of Contents that included all of the types numbered (1 for adventures, 2 for towns, 3 for encounters, 4 for shops) would let someone jump into their binder to a table of contents page for the section that the user could scan for the page number of the supplement they wanted.
TL;DR: I think one page adventures could work if there was a chance of re-usability (such as with themed adventure generators). Without that, the one-off adventure might get undervalued by customers. The one-page format would provide benefit in more than just adventures, and the contents could fill a binder that would be an easy-reference GM's toolkit if the supplements are numbered by type and item.