Why do you think the NSA could have put the industry on memory-safe languages?
Even if they wanted to, I highly doubt they could push the industry to do that. The industry does what it wants to do, and rewriting tons of software was far from its priorities. There were no LLMs back then to help with such a massive migration.
There's also the fact that rewriting software tends to introduce a lot of new bugs.
The U.S. government could have required all new software for any government-procured system to be written memory-safe languages, thus making it ubiquitous. This could have been phased in slowly with a few years of on-ramp time to allow for industry to acquire the relevant skills.