But would you buy an 80-page adventure for $14? Could you even find one for $14? What about a 32-page adventure?
Dungeon 96: $8 for 71/89 pages of adventures (Excluding letters and ads) = 11.25c per page
Dungeon 95: $8 for 69/99 pages of adventures (Excluding letters and ads) = 11.6c per page
Sunless Citadel: $10 for 32 pages (No ads) = 31.25c per page
Forge of Fury: $10 for 32 pages (No ads) = 31.25c per page
Bastion of Broken Souls: $10 for 48 pages (No ads) = 20.8c per page
Return to the Temple of Elemental Evil: $30 for 207 pages (+2 pages of ads) = 14.5c per page
The Banewarrens: $18 for 127 pages (+1 page of ads) = 14.2c per page.
Theoretical 80 page adventure for $14 = 17.5c per page
Proposed 50/67 pages for $7 = 14c per page
Proposed 20/33 pages for $7 = 35c per page
Theoretical stand alone Dundeon 70/100 pages for $10 = 14.2c page.
Yes the current format of Dungeon has the lowest cost per page of adventure, but you also have advertising to reducing this cost. I would also argue that not all of Dungeon is usable as there is always at least 1 adventure that I don't like. Note however that the theoretical 80 pages for $14 comes out more expensive than the mega-adventures which only have nominal advertising and only slightly less than the Bastion of Broken Souls. Yes Dungeon is glossy and color, but how much real benefit is this really worth.
If you like Poly then this does work out to a great deal, if however you are like me and don't need poly (I don't hate it I just don't use it) then you are going from the best price per page for adventures to average price per page for 2/3 Dungeon issues and highest price per page for 1/3 Dungeon issues. This is why I will only buy the 2/3 Dungeon issues.
[Edit: Just checked another as well. City of the Spider Queen: $30 for 175 pages (+1 page of ads) full color glossy = 17.1c per page]