But they were really, really primitive, remember?
Here’s the Max Planck Institute’s page on Neanderthal tools specialized for working leather:
Microwear analysis conducted by Yolaine Maigrot of the CNRS on of one of the bone tools shows traces compatible with use on soft material like hide. Modern leather workers still use similar tools today. “Lissoirs like these are a great tool for working leather, so much so that 50 thousand years after Neandertals made these, I was able to purchase a new one on the Internet from a site selling tools for traditional crafts,” says Soressi. “It shows that this tool was so efficient that it had been maintained through time with almost no change. It might be one or perhaps even the only heritage from Neandertal times that our society is still using today.”
These are not the first Neandertal bone tools, but up to now their bone tools looked like stone tools and were made with stone knapping percussive techniques. “Neandertals sometimes made scrapers, notched tools and even handaxes from bone. They also used bone as hammers to resharpen their stone tools,” says McPherron. “But here we have an example of Neandertals taking advantage of the pliability and flexibility of bone to shape it in new ways to do things stone could not do.”
No doubt they were overly familiar with both substances. They would probably have adapted very well to steel and plastic. Almost everyone does.