He’s correct, I’m a single-man team hobbyist, trying to achieve a open world of say, 4x4km floating islands procedurally. I’ve been messing around with it for about a year and a half now, and I’m not far yet… but, it’s a hobby for me in my spare time
Reseach how many people a team like Bohemia Interactive has to work on the Arma series. Now do this x 40-60 hours a week. Then do it for you and your friends until you reach the same time. Multiply by 3-10 times for no experiece…