When talking about physical features like that, sure, but the digital realm is very different. I downloaded a game on my phone that features microtransactions. There are abilities to purchase that are built into the game, but you have to pay to use. But the game itself was free. And I haven't spent a dime on those features, but they're there if you want to use them. Seems like a good balance.
Especially when looking at the pipeline to create new content, just because the content is on the disk, doesn't mean that it's part of the original content. It's a license to play, not ownership of everything on the disk. Not all instances are like that though, Mass Effect 3 DLC for one. That mission and story arc are considered by most to be integral to the overall story of the series, and to set that aside as extra content to be paid for doesn't seem like a good use of that system.