What makes devs remove functionality from subsequent games in series?

[Shortie]

Whenever developers removed a feature in a game it's usually I find to bring it back at a later date in a new game in the series. Usually it's the most popular features that end up being removed from the game that they know their user base are going to miss and then when they leave it long enough and bring it back to a new game in the series, consumers are excited to see it back and will jump on the game even paying full price for it. It's the developers way of milking more money out their customers which is a shame but if people bite then they will keep on doing it. 

[Scorpion]

Developers might simplify mechanics to attract new players, streamline gameplay, or focus on specific elements. It can be frustrating for fans!