Don't go into business in you own al. A real entrepreneur would have seen what happened in front of him and thought how do I monetise this? First recognise there are a bunch of people who are either numpties/lazy. First opp is to offer free session showing how to change a tire. To make it fun you then add in a comp for who changes it the fastest. By this time the juices are flowing and you will be able to sell the books, the work stand, the tire levers etc. Repeat with basic bike maintenance but small fee and free coffee. Ditto more sales of gear. At the same time you educate about different components etc and watch the dura ace fly out instead of the Deore only to be replaced by ultegra when the DA had prematurely worn out.
By the end if this, you have a bunch of new pleased customers. They will be buying more stuff, more engaged etc.
The other option is to smirk and take the piss out of a lazy numpty. And LBS moan about how tough trade is
Next time the guy should use HIS brain and use the net to buy the inners!