Nintendo has the best achievement system because they have none. Approaching game design with a "one size fits all" approach is stupid. Additionally, you have to consider that multiplatform games can have their entire achievement lists on a Nintendo console, yet most third party developers choose to omit them; that should give you an idea how much value they think achievements add to their games.
Also, if achievement systems had a significant impact on keeping gamers in an ecosystem, then why do so many people have no problem whatsoever to leave Xbox behind? Microsoft was the first company to implement an overarching achievement system.
The truth of the matter is that outside of a small percentage of gamers who care about achievements, there's not even a middleground, meaning that the vast majority doesn't give a damn. Because at the end of the day an achievement system is nothing more than a more elaborate online leaderboard for high scores and the vast majority of gamers doesn't care about online rankings in any other form either.
Even the original poster recognizes that achievements are about a false sense of accomplishment. Indeed, it's about making people buy more games to drive up a score, because making better games as an incentive to get people to buy more games is much more difficult.
Is Xenoblade Chronicles X one of the best RPGs ever because its achievement list has more than 500 entries? Of course, because that's what anyone ever talks about when they mention the game.
Legend11 correctly predicted that GTA IV will outsell Super Smash Bros. Brawl. I was wrong.
