It's indeed surprising that replacing the elementary particle with a string leads to such a big change in things. I'm tempted to say that it has to do with the fuzziness it introduces.
When you click on a link, you are replicating the string of code that it links to. Replication of code sequences isn't life, any more than replication of nucleotide sequences is, but we know that it sometimes leads to life.
You have that one basic string, but it can vibrate in many ways. But we're trying to get a lot of particles because experimental physicists have discovered a lot of particles.