How do you think meterpreter would be controlled by an AI? Do you think there should be an AI that will automatically figure out a way to hack into a system or escalate privileges?
Regarding other tools like nmap and metasploit - they are frameworks which let you run modules specific to certain exploits. Metasploit has countless of new modules being developed all the time. And nmap has its own scripts to target new kinds of attacks.
Though the basic functionality of nmap will not change anytime soon because network protocols are largely the same since 10 years ago.