In Canada, the governments have been actively discouraging the solo practitioner practices for GPs.
Turns out that telling your patients to go to ER or a walk-in clinic every weekend/evening/holiday/illness/leave isn’t the best care.
And continuity of care if you retire/fall ill is rarely done well.
Multi-practitioner clinics can share an on-call schedule or evening/weekend hours, get bonuses for doing so and save money.
Also allows for flexible schedules. Want to work 3 days a week? Sure! Had a child and want to still work the occasional weekend only for a bit? Ok!