The cost to maintain and develop SSO has nothing to do with why it's priced the way it is (very few things in our industry are priced strictly according to cost). SSO costs extra because it's one of the most effective market segmentation tools: the people that require SSO in order to use things are generally (though not exclusively) price-insensitive.

This upsets people, but the larger companies that pay the SSO premium are subsidizing the smaller companies who don't care. I'd rather not pay an SSO tax either, but I'm even less excited about using tools from companies that are going to vanish because they're not generating revenue.