Actually, I did take a look at composting toilets.
Two issues with them though.
One, I only have the one bathroom. It's not that big. There literally isn't room in there for a second toilet. (And no I wouldn't remove my "normal" toilet to make space for it, nor would I want a composting toilet in some other room.)
In my case, I needed to minimize the water OUTPUT from my house to save on the wastewater bill. By reusing laundry water in the toilet, I reduce the total amount of water used (as compared to doing laundry AND using tap water in the toilet)
If I simply ran my laundry water to the drain and used a composting or sawdust toilet, that would be that same amount of water. By reusing the laundry water to the toilet, I minimize water use but still have a "Normal" toilet.
Nice for when people come over to the house and I didn't have to tear up the bathroom or do any kind of remodel.
I think that in a new house or heavy remodel, it would be easier to design for composting toilets, extra water-saving devices, gravity fed systems, rain-water flushing, etc.
The book
HUMANURE is a really good read. It will make you question how we deal with human waste. Anything by
Art Ludwig on graywater and cisterns is also very good.