Comparisons are a bit more complicated. Development costs have definitely increased, but then production is cheaper (going from cartridges to optical media, then to electronic distribution), and distribution costs drop as electronic distribution eats away at bricks and mortar shops. It's also a far larger market now, with top titles heading north of 20,000,000 copies sold, and revenues topping a billion dollars. If you look a NES figures, you'll notice quite a few of the top titles are from Nintendo and their figures are greatly increased through being bundled with the console. Also developers are not as tied to single platforms as they were back in the day.

I'm not against launch day DLC. You make a good point by noting how it can create a lower priced entry-level product and increase choice. I'm more concerned by the "freemium" titles that I feel are dishonestly presented as being playable without needing purchases. EA's Dungeon Keeper has become the poster-child for dishonest use of the freemium model. I found Civilisation Revolutions on iOS to be a demonstration of how DLC can be done badly. They sold the product at full price on launch, and then later dropped the price and started inserting adverts (for other games and DLC) in to the game. Multi-player mode, which was standard in the Civ franchise, was added later as DLC. They also added additional units and things to the game, as DLC, and made it so the computer player already had access to these things. Also, players without DLC additions were at a disadvantage in multi-player when other players had bought them. As someone who bought the game full-price, I was a bit narked off.

Overall with launch day DLC, whether we get a great deal varies between products, and adjusting for inflation is a crude method of gauging value for money. I think we have to judge it by title.