depends on your definition of "productive". you may not care about money yourself, but it's the money that makes research go around. what about salary for your postdoc/techs? maybe you can live in a homeless shelter...
will you get paid more as 80/20 or 100/0? 80/20, sometimes substantially more
will you be more flexible geographically? 80/20
will you be more likely to get hired? 80/20
will you be more likely to get a grant? 80/20
will you be more likely to get published (in any journal)? 80/20
will you be more likely to get tenured somewhere? 80/20
will you be less likely to lose your job? 80/20
on the other hand
will you be more like to get a basic science grant? 100/0
will you be more likely to get published in Cell, Nature, Science? 100/0
will you be more likely to get HHMI? 100/0
will you be more like to get the Nobel prize? 100/0 (don't know ANY with 80/20 who has a Nobel prize...although there are a few 0/100)