A 2013 comparison from Wikipedia.
Nintendo has 5200 employees. Revenue was 6 billion.
Electronic Arts has 9370 employees. Revenue was 3.8 billion.
Activision has 7061 employees. Revenue was 4.6 billion.
These numbers are outdated but it shows that Nintendo's revenue would significantly decrease as a third party publisher.
I mean EA and Activision with their DLCs and microtransactions still didn't make more money than Nintendo. This was both The Wii U's and 3DS worst year, yet despite having less employees than both, they still had more revenue.