You may, technically be correct. But, it one took this to mean that they should not scan slides and store them on either hard disk or optical media.. or wait until they can scan them at just the right resolution, it would be a grave mistake.You are in error if you think that digitizing your slides is
"preservation". There is no indication that CD's or DVD's will
last as long as the color dyes in well processed, dark stored color
slides. Rather, scanning and digitization are a convenient way to
adjust, retouch and prepare for printing those slides that you wish
to make high-quality prints from.
Also, to even remotely get the full detail present in properly
focused, well exposed color slides you need a dedicated film
scanner with 4000dpi optical resolution.
Fires happen. Floods Happen. Vandals happen. More importantly people generally have more than one children... and, some of those children do NOT have children or care to pass on precess family images.
Scanning, storing AND DISTRIBUTING to a wide array of relatives and children is THE safest way to ensure that future generations can enjoy the photos.
One has to take into account FAR more than simple technical issues when talking preservation.
In the past, photos were split up among the children and each got a small percentage of the total inventory of images. These days, once they are scanned, every child can get every picture. They might not have the original; but, they at least have a decent copy in a form that THEY can duplicate and distribute in turn.