I have actual concrete data about this¹ and unfortunately the percentage is much larger than you realise.
I'm still under NDA until 2024 but it's in the region of 60-80% of sales for certain games, especially RPGs which seem to get pirated the most.
People like to cite hugely successful products being DRM-Free or something as proof that it works, but for every project that works well there's hundreds that die in obscurity.
Also, people like to back a champion to "prove that it works" which inflates the margins of the champion product.
¹ - based on my time at Ubisoft, and based on Ubisoft titles only and when accounting for other differences between franchised games.