That's just not correct. I have several raw books that were signed in the late 80s and plenty of "real" books that were signed/inscribed even earlier than that, and none of them suffer from the ink bleed-through that you mention.
I'm not saying that it couldn't happen period, but it's much more likely that the bleed-through happened while the book was still freshly-signed, and it was due to the very specific mix of ink & paper being used on that particular occasion.
Another factor, and I am no color touch expert, relating to bleedthrough is the condition of the paper. If the 'Tec had a lot of damage, including some of the finish and maybe some of the paper fibers being lost, bleedthrough makes a lot more sense. It is actually something I've thought a lot about when having low grade keys signed. Often, when you see bleedthrough on CT areas, it is the most evidenced when there has been damage. Many many SS books are pristine examples and should have fewer bleedthrough issues. All very valid points, though.