A standard alternative path to superhuman intelligence (which is the precondition for a singularity.. NOT AI specifically) is IA: Intelligence Augmentation. I.e., work on making humans smarter than they are. It's reasonable to say that the Internet has achieved a lot of progress in that direction already. Get brain/computer interfaces working, and suddenly everyone will gain 10 effective IQ points through instant access to encyclopaedias and calculators. Etc, etc.