Electrolysis is guaranteed to have an effect, but as you say, it's expensive, time consuming, and hurts a LOT.
How many months and how many laser sessions have you had? It can take a while for its effects to be apparent, it can be hard to see how dense the hair is. I'm doing electrolysis on my face, but if necessary, will probably do laser on body hair, simply because I just can't imagine going through the electrolysis process for that much area...