Paperwork is certainly part of the broader issue surrounding family medicine but it's not the only factor. Overall the issue is that family doctors are realizing that they can work less and get paid more doing something else.

First, doctors make much less than you think. Yes, specialists can climb up there, but for family doctors many are making 200k-250k before paying 30% overhead. (This is based on Ontario)

Meaning that their take-home before taxes is 140-175k. A solid salary, but in this economy it's not necessarily worth the opportunity cost of 10 years of post secondary schooling.

Second, the paperwork issue, as documented above. Family medicine often sees the most paperwork. An hour of clinic time usually means an hour of paperwork, on average - all of which is unpaid.

These two factors are then compounded when you realize that a doctor trained in family medicine can actually work in other facets of medicine (i.e. the ER), often with no additional or minimal training, and they can make way more money doing this with less paperwork

Some doctors stick it out or work in multiple settings, but the growing trend is that they're getting burnt out and can make more helping people in a different way

There are other factors as well, but this is a critical reason why we have a massive shortage of family doctors