The games are only temporarily marked down, what you are observing is discounting as a promotional tool because discounts get in front of more people than full-price games.
These are not perpetual discounts that would make the defacto real price be the discounted price. After the launch week/s the game price will revert and eventually fluctuate from being occasionally discounted, included in bundles, given away etc.
Discounts are an important sales tool for games - you can see major publishers today are pretty much constantly offering big discounts on one store at a time. Steam etc all have discounted game lists, websites track game deals, there's a huge subreddit for them at r/gamedeals, there's sites tracking the lowest-ever prices for games etc.
