Imagine it's 2010. For the first time in almost a decade, you hear news that there's a new XCOM game being developed.
This is the XCOM you're told you're going to get.
Imagine it's 2018, and you've been waiting 6 years for a sequel to Diablo III.
The XCOM we were promised in 2010 eventually became
The Bureau: XCOM Declassified. Despite modeling itself on the popular FPS genre, it was not a success story. However, the negative reaction to its announcement triggered the development of a more traditional XCOM sequel/remake, in the form of
XCOM: Enemy Unknown, which was so successful that it revitalised an entire genre.
It became the "popular game" that everyone else copies. Now we have Gears of War tactics games and Mario tactics games, etc.
In 2010, you could have argued that XCOM style tactics games were dead. Nobody likes them and they're just bad game design. And yet, fans demanded that XCOM be the best it can be while staying true to its brand/niche, instead of just playing it safe by becoming a different game entirely.
Imagine jumping onto a Diablo forum in 2017 and asking for the next Diablo game to be a mobile phone game, and then trying to hide your subjective preference for mobile games by saying "it's objectively true that mobile games are more popular than PC games".
In fact, don't imagine.
I really find it odd that there's any need for a discussion around the popularity or financial success of the original Baldur's Gate games. Those games are why we're all here.