upselling should also be avoided when the additional content could give an advantage in multiplayer. Battlefield is a repeat offender but at least if your competent it doesn't detract from the carnage significantly.
its going to be a continuing problem because these kinds of setups are going to lure potential investors.
How are you going to sell your game?
$30 on steam.
What about extra/addons/expansion/dlc?
Our research has shown that level headed customers don't like this, we will make a faithful sequel.
That will get you the response, "Well, all the other studios are doing it so we will invest our money there were we are more likely to get a bigger return".
Unfortunately level headed customers are in the minority these days.