For most people they are but you'd be surprised at how many basly-placed or -configured resolvers there are out there. Consider a nationwide ISP with resolvers

For most people they are but you'd be surprised at how many basly-placed or -configured resolvers there are out there. Consider a nationwide ISP with resolvers on East coast and West coast. For "failover" they assign them in random order to customers. That means 50% of the time a customer of the ISP in Tampa will appear to be coming from a resolver in San Jose.