We have an answer on stare decisis and precedentstare decisis and precedent.
After the Supreme Court decides a case, if a lower court rules on a case with the same fact pattern as the previously decided Supreme Court case, they are bound to come to the same outcome.
They can arrive at a different outcome only if they find aspects of the new case that materially distinguish it from the Supreme Court case.
Regarding the specific case you mention, my reading of AT&T Mobility LLC v. Concepcion 563 U.S. ___ (2011) is that it holds that consumer contracts can include clauses that prohibit class-wide-arbitration.