500k to 1 million sales allegedly according to this site.
https://steamspy.com/dev/Paradox+Interactive
Seems like a success to me, if HOI III did the same thing after its
third release with an established player base (over a longer period of time). Why should the period be dead?
Whilst "up to one million sales" might sound good how many of those where heavily discounted "sales" compared to my pre-launch purchase? The chart you quote, which shows I:R in nineteenth place, also shows the top spot held by a game originally launched in 2015 with sales of up to ten million and an average game run time of three times I:R. Indeed many of the places above I:R are also held by "old games".
So, more likely, that chart shows I:R to be more a failure than success, surely?
I long waited for something like I:R having played "EU : Rome/Rome Gold/Rome VV" to death over the years I used it, to me the period of Classical Antiquity has a magic charm and should be a stable product in ANY game's studio output. However I certainly agree that the games up to v1.5 were rather shaky . . it wasn't that you couldn't play the game, it was more you seemed to play against issues within the game.
Please remember everyone that PDX are a company whose purpose is to make profit for if no profit then they can neither update old games or design new ones. Sadly I too often see an attitude amongst far too many that, having bought the game and/or the DLC's in a "bargain basement sale", they then sit back taking an attitude that PDX owe them. NO, get real those of you that do!
If PDX return to I:R and I agree with those that say it would be far easier for them to continue development than start afresh then they would be wiser to create v3.0 as a "new product", advertising it's long pedigree and development in v2.0 but ONLY to be played by being bought by all, not an automatic update. Then they have the chance to increase the profit the game overall will have brought the studio. Existing players will then have two choices, buy the "new game" or continue to play v2.0.
If you don't like my words please take into account what happens with most software? Very few offer "lifetime development"?
. . . in any case come Windows 11 many of us may lose a lot of our games as Microsoft's "marketing strategy" will force games studios to adapt old games and make new ones ONLY for that platform . . lest non-compliance with Microsoft "orders" cost them their business!