Random thoughts:

Fitness could be a big factor of spreading seeds widely, but not necessarily the only one-especially for survival over the long term, in a rapidly changing world.

A good question is what would define "fit", and fit for what?

When circumstances change rapidly, more than before, would some of the previous definitions of being "fit"change with it? Specialization for survival for one situation could be seen as a benefit one day, and be a hinderance the next, with a new playing field.