I'm not sure they ever did. They should imho be teaching the ability to learn and adapt to changing and emerging technologies, and to think critically. I'm still using the mathematics I learned in college, to understand things that didn't exist back then such as elliptic curve cryptography.
We seem to instinctively err on the side of avoiding any short term cost, no matter how potentially grave the consequences in the future if the probability of those becomes low or obfuscated.
You can see this not just in backups, but in lifestyle choices, business decisions, construction, natural resources, financial speculation ...
Any situation where you can say "it does not happen often, but if it does the results will be catastrophic", you can bet that the risks will be unhedged.