I'm not sure, maybe it's just because there's no true superstar sprinter at the moment that it looks that way but eventually there'll be a time when a new Jamaican or USA phenomenon comes around. Coupled with better training, equipment and maybe mentality than Bolt, it's bound to be broken sometime in our lifetime I'd say.
Same story for Maradona and Messi, Michael Johnson and Bolt, Bubka and Duplantis, even Jordan and LeBron to a lesser extent, ... Johnson's 19.32 was deemed extraordinary but it "only" stood for 12 years and in the end Bolt shaved more than a tenth of a second off of it. Eventually, there'll always come a faster person.