Actually, it takes two things to combine to damage the alternator, a bad cell and revving the engine. At low RPM the alternator doesn’t put out enough current, even to a dead short, to cause it to overheat and burn out the diodes. As you rev the engine, you also rev the alternator, increasing the current out and increasing the heat the diodes are subjected to.
The reset procedure after replacing the battery isn’t that difficult, you shouldn’t let the dealer scare you away from doing it yourself. Once a 5 year old battery begins to give you trouble, replace it immediately. No testing needed, just do it, its cheaper and easier in the long run. If you had a red battery light on the dash before the battery went dead, then the diode was the first thing to go, it took the battery out, not visa versa.