NATO was obsolete when the Soviet Union fell apart. The core purpose disappeared. That was 30 years ago - a generation.
No, NATO will become obsolete when Russia stops invading her neighboring countries, violating the post-WWII peace order and the firmly established principle of the inviolability of the borders of sovereign nations.
When we can be sure that no further aggression or threat is emanating from Russia, then NATO will have served its purpose.
But as long as Russia continues pointing roughly 5,000 nuclear weapons at America's heartland, NATO remains a bulwark for America's survival.
Regards,