What real incentive do they have to go all the way up to 100% on behalf of the employee? If they ended up at 90% they could probably add 5% and get a very similar result (employee happiness).
The incentive is to create an actual loving and supportive culture which they believe pays off. They also feel like it’s the right thing to do given their values.
They are one of the top rated corporate cultures in the world and recently valued at around $2B 10 years in.