I'm not speaking from experience but.. I think even is different to any other split in the same way free is different to any other price. It creates an implici

I'm not speaking from experience but.. I think even is different to any other split in the same way free is different to any other price. It creates an implicit definition of "fair." A 60%-40% split is implicitly valuing founders' previous contributions, potential value, experience, etc. These are very hard things to estimate. If you ask everyone to quantify their contribution to a success and add up all the percentages, you will usually get a total >100%. An even split avoids all those problems by putting them aside and agreeing to a definition of fair. Humans understand egality intuitively. They are usually emotionally comfortable with it.