Why do uber driver accept ride and have the customer cancel

Just like the title says. the amount of time I get an uber driver who accepts my ride and either don’t start driving no matter how many time I text. Or just start driving even farther away. Today I got my uber a little early from work so I could leave at reasonable time. I check back when work was over and the guy hasn’t moved in ten minutes. I texted him and no response. I had to cancel and found out I would’ve paid a ten extra dollar higher fee for new ride. I just want to understand why accept the ride if you just going pulling the customer along. I don’t even mind canceling for the driver if I get some sort of response.