Because I have about 10 independent shops closer to me than my nearest Pep Boys.
PB isnt any cheaper here and Id rather support a small business (especially in our current financial environment).
But, you do you and try to fire up an argument.
I'm with you, we don't have pep boys here but we have several pep boys like chain garages and I wouldn't go or send someone to them unless they were the only option in town in an emergency situation. And even then, I'd have to warn the person that they will try to rip them off. Not saying all local garages are angels either, but around my area all the chain garages routinely try to ripoff unsuspecting people who don't know any better. As trustworthy as a car dealer.
By all means people can go where they want, but I'd put that up there with going to the dealer to replace a water pump out of warranty. Should be easy enough to ask around to see who has a good trustworthy local garage, and give them the work and save some money. Dealer can handle my expensive or difficult warranty work, otherwise they would never touch my truck. My cousin owns a garage in town, that makes my choice super easy but even if he didn't, I know another local garage I would be going to.