u/QcYoloGuy

Ok so,

40-60 average staff × 10-13 years × $180k-$240k/year = roughly $72M–$187M payroll burn

Outsourcing / QA / tools / platform / audio / cinematics = $20M–$50M

Marketing / launch / publisher support = $30M-$70M

So somewhere between $140M–$250M

For reference

Immortals of Aveum ~$125M total: ~$85M dev + ~$40M marketing/distribution

BioShock Infinite - Analysts estimated ~$100M dev + ~$100M marketing (Kenny boy said it wasn't true)

Edit: Don't take this too seriously, it's a discussion starter tbh, not treated as fact. Ken called me and was very angry with me. He said it has only cost them a few Lego sets.
Sources I used:
https://www.linkedin.com/company/ghost-story-games
https://job-boards.greenhouse.io/gsgcareers
https://ir.take2games.com/static-files/8cd3f86a-d4bd-4818-84c7-2187bf7bbf41
https://www.videogameschronicle.com/news/amid-development-hell-claims-bioshocks-creator-says-ditching-work-should-be-viewed-as-a-luxury/
https://www.consolecreatures.com/ken-levine-next-game-struggles/
https://www.trueachievements.com/n53671/aaa-game-development-costs
https://www.tweaktown.com/news/110687/two-things-are-causing-aaa-game-development-costs-to-hit-dollars300-million-per-game/index.html
https://www.gamedeveloper.com/business/the-cost-of-games