They will "last" just as long, but alnico magnets will very slowly lose some of the magnetism over time (10 years or more) making them a bit less powerful, a bit warmer and more complex sounding. This is considered desireable by many players. That is why some many old vintage pickups have a slightly different sound and are worth a lot of money.
Ceramic mags stay the same and are a bit....harder and brighter sounding. They don't "mellow" with age.
Whether this is good or bad depends on your taste.