Peak of popularity ?

Set IV was a bad set IMO. It had too many minor nations, and didn't have many "big plastic" BBs or CVs. That just didn't sell. RB was listening too much to the vocal minority fans. He tried to reverse it with Sets V and VI, but it was too late.

Set IV is popular with the minor nation players and with the more historical players because the set filled in some important gaps. But it wasn't attractive to the mainstream. RB put too many "corner shelf" units in that set. I blame that set for the rapid demise of the game. Especially within WotC management. RB's budget was significantly reduced for Sets V and VI. ( I know that from personal discussion.) He was hoping he could hold on for one more set, but it wasn't to be.

RB himself posted way back then that War at Sea was the "Aleutian Campaign" project at WotC. I have talked to several ex-employee's that said the land game was supported by somebody in senior management, but the sea game never really had much internal interest. Sales of the first set surprised everyone, but it still wasn't enough to make the bean-counters happy. Evidently the game/comic book store owners were the one's who demanded a second set. The game was bringing customers into the stores they had never seen before. That I was told directly. My guess is that later on the interest of the "brick and mortar" stores declined as on-line sales began to get a lot of the business. The rapid decline of the land game at the same time probably didn't help. That game got 11 sets despite terrible sales of the later sets. (Looking at you re-scale!) Again, the land game evidently had a management "benefactor" that the sea game did not.

Bottom line, War at Sea was never big enough to really make the profits WotC/Hasbro wanted. Probably another way of saying it wasn't "Magic the Gathering."

I think there would have been a final set with Set VII if it hadn't been for the Dungeon's and Dragon's personnel purge. RB's main job was working on Dungeons and Dragons. The A & A miniatures games were literally "side projects" for him. He lost his job when WotC eliminated much of the D & D development team because the game was not doing well. How he managed to do all of that is beyond me. He was lead developer for all three A&A miniatures games, plus a lead developer for D & D. For all the nitpicking we do over the game it is amazing to me how much WWII historical and technical knowledge he had.

I "discovered " WAS after playing that failed WOTC star wars game starship battles and lots of people mentioning that it should have used WAS system instead.

I think it was you weeds who said that WOTC had asked RB about maybe looking into fixing the gameplay of Starship battles and while they decided to let starship battles die after one set it would have been interesting if other games like it adapted WAS's gameplay system in more mainstream themes perhaps it would have given the game a bit more exposure and appreciation of the game system. Historical theme aside WAS is still a very fun game to play which you cant always say about many wargames.