You're right that games are a market where consumers have lots of choice. If you watch the choices people make, though, you'll see that they don't care about whether a product is buggy and slow.

The top game on Steam for many months now is PlayerUnknown's Battlegrounds. It has a "mixed" rating, with only 49% of reviews giving it a thumbs up -- by far the lowest rating of any game in the top 20. The reviews tell a story of how bugs, lag, broken servers, loot crates, and rampant cheating add up to a barely-playable game.

And yet, no one cares! It continues to top the charts, both in sales and cumulative play time. If we think about why that is, we might come up with non-monopoly explanations for why buggy software proliferates in other fields.