Background: I've been a IT hiring manager for 20+ years now, with about 600 hires (and salary negotiations) in total. About 70% gamedev related, and the other 30% classic IT.
I have tracked all those numbers over the last 20 years. They are 50-100% higher across the board; And that is base salary on-hire, without bonuses.
A senior developer for 60K? Show me, and I'll hire 10. Make that 20. On the spot.
Last year I hired a graduate in Bulgaria for 80K/year base(!) salary. Granted, he was the best of his year, and had some nice side projects.
According to your numbers I should not exist. I started my career in the 90s, and never earned below 60K/year.
I suspect something might be off with your sample selection. Or maybe people are just under reporting their numbers. Not saying you are intentionally misleading, but these numbers just don't compute.