or they miss-estimated their market size and growth. I don't think most people care about DNA testing.
I'm not saying this is the cause, but they had a chance to be good guys and decided against it.
For example, carrier screening, to see if you and your partner both carry recessive variants that may result in a rare genetic disease in some of your children: impossible with 23andMe's setup, but useful to a huge number of couples, and already common practice for some ethnic groups.