Well you guys were talking about sales so I did some googling. Kind of interesting but I dont know how relevant it will be to the argument.
https://wccftech.com/divinity-original-sin-2-85m-revenue-2017/This basically says they generated $85 million in 2017, placing DOS2 at the ninth spot in 2018s premium PC market chart
PREMIUM PC
1 PlayerUnknown’s Battlegrounds - $714M
2 Overwatch - $382M
3 Counter-Strike: Global Offensive - $341M
4 Destiny 2 - $218M
5 Grand Theft Auto V - $118M
6 Battlefield 1 - $113M
7 Minecraft - $92M
8 Guild Wars 2 - $87M
9 Divinity: Original Sin 2 - $85M
10 Tom Clancy's Rainbow Six: Siege - $67M
The source is coming from something called SuperData Research, link is on the website if interested.
Edit* wow that took a bit, here is what i could find for sales for the year on BG1
At $15.7 million in revenue, it was the country's seventh-highest-grossing computer game of 1999
https://en.wikipedia.org/wiki/Baldur%27s_Gate