It's an elegant rule as written. Sure you might get lucky... pickpocketing a blind eighty year old person in their sleep. As in, when the DC is very, very low. Remember that a d20 roll has a 10.5 average, so what you've got is 50/50 odds of success at DC 10 checks (assuming no Dex modifier). Sounds reasonable. 50/50 to pull off something easy and no chance of pulling off something hard.
Keep in mind how learning curves tend to work. A professional pickpocket could teach you a lot of important tips in a couple hours. Things like selecting a reasonable target out of a crowd. Getting truly good at it takes time, but some basic training can make the difference between improvising and doing something intelligently but without much experience.