Why is it that most tubing manufacturers provided the most fragile decals??
 

Pretty much on most bikes it is the tubing decal (Specially the older Reynolds and Columbus.) that gets most beat up, because they are usually dry transfers with no clear coat over them. Replacing them could be very tricky too, as the genuine decals are only microns thin and you cannot do any positional adjustments the moment it touches the frame tube surface.
One would think that these decals would have had more attention from the bike companies and the tubing manufacturer as big selling tools for the bikes....

If more people clamped the seatpost rather than putting the clamp over the decal, more would have survived.

The repro Columbus vinyl decals I’ve seen are virtually identical to the originals and can be perfectly positioned using “wet” water.

Probably so they could not be lifted off and re-stuck onto inferior tubing. (And mark any robust tubing decal as a copy or fake.)

Exactly. If a Reynolds or Columbus sticker was on there- it was on there from the manufacturer- if you even looked at them too intently- they'd flake off into a bazillion pieces/layers. And as I understand, you didn't get aftermarket decals.

Until it didn't so much matter and even good tubing was looked at asl just old-fashioned, heavy, rusty steel- and then the decals just changed into normal stickers.

In the 197o's Columbus provided a transfer or a sticker- no rhyme or reason

Many Italian makers never declared the tubing.
the French lied, tubing was aspirational.

To provide us with hours of entertainment trying to identify a frame. See also; serial numbers.

Chombi1,
As you stated.....We must remember, that the decals, many now nearing 40+ years old were made from a very delicate material that at its inception was fragile to say the least, and few were cleared.The adhesive was also water soluble, much like old Le Pages or Elmers glue
Todays decals many made of a clear vinyl and some are clear coated which has helped their survival immensely.
With all of the environmental cycles that they have undergone, I am surprised that have any survived at all.
Best, Ben
BTW, I bet that there was not a lot of thought about how they would hold up after 5-10 years of riding much less the 40+ years we are expecting now.

Tubing manufacturers were concerned about misrepresentation of their products; a fragile decal prevents a fraudster from lifting to decal from a legitimate frame to pass off a different frame as using the prestigious tubing. Until the early 80s, Reynolds tubing decals were multi-layer, with each layer a different color, die cut to show the other colors beneath. You only get one chance to apply that type of decal. Early Columbus decals were printed on foil that easily tears.

The good thing is that more robust decals are available through a few different sources. I buy them through Velocals.

Trying to remove modern vinyl decals will also result in destroyed decals.

The only difference I can see between the modern and original Columbus SLX decals is that the repro will have a visible white edge when applied (the thickness of the decal). Other than that, I think they are virtually identical.