1) Sahi is aimed at testers and not developers. Its focus on strong record and playback and on simple scripting, is primarily meant for testers in the Indian industry. These are people who are good at manual testing and automation with tools like QTP, but are not from a programming background. Selenium and Watir on the other hand are aimed at testers and developers who are fine with programming. Unfortunately for Sahi, testers in India who use Sahi, do not blog or voice their opinions on the internet, or contribute back in forums. (Most of those who do, are good technical testers.) That meant that there was no viral aspect to the spread of Sahi.
2) Very little emphasis was made on Sahi's website or in the program to collect user data. No testimonials, no newsletters, which meant that people were not informed of developments and good user stories to boost their confidence. While the program continued to evolve with releases every two months, few people really saw the progress.
While the first and third problem cannot be solved easily, the second is quite addressable. A new section for testimonials and user stories has been added to Sahi Forums. This blog you are reading is being updated with new developments. Updates and news of Sahi can be followed via twitter at _sahi. Presentations on Sahi will be available here
If you are a Sahi user, tweet with #sahi so others may know. If you have a user story do post on the forums.