[philpem]

The maximum useful resolution you can really get out of offset-printed magazines is around 200dpi. Scanners have been able to do 400dpi for many years, and have been stuck at the 1200dpi plateau for about as long.

Sometimes you just don't need a better scan, because you're just doubling up on data you already have.

[skissane]

There are lots of other issues that can occur with scans beyond just the raw resolution: misaligned pages (part of the text accidentally cut off from the scan), accidentally skipped pages, colour illustrations scanned in black and white, etc.

With a sufficiently robust QA process, you may be able to catch most of these issues. However, you can never reduce the probability to zero, and people scanning old computer manuals don't always have the necessary resources to implement the most robust QA process.

[Mountain_Skies]

There's also some types of papers and inks that don't scan well. Omni Magazine used metallic inks in some of their issues, as did many tech magazines of the period, probably because it looked futuristic. These don't scan well and even if the content of the page is preserved, the look isn't. At which point it becomes as question of how much of the value of storing artifacts of the past is in the presentation in addition to the content?

[im3w1l]

I'm not part of this scene and I'm not a collector, so I my dispassionate perspective is that at some point the cost of quality insurance is greater than the benefit. For a very important issue of a very important magazine, of course, keep it around. For a less important one, maybe retaining 95% of the data at 5% of the cost is good enough.