I take it you have not been to Amsterdam or Berlin. I live in the latter and, while there certainly are homeless people, it is absolutely nowhere even close to SF per capita.
No, not really. "Importance" is a rough proxy for legacy and influence. This is why one can say without any trace of subjectivism that Shakespeare is the most important writer of the English language, or Kafka the most important writer in modern German, etc. Maybe this is slightly less rigorous in the case of '2666' which is still a relatively young work, but it is widely hailed as a landmark novel.
An easy solution to this is to give point-based weights to achievements and cap the max total "points" any given game can have, allowing a developer to have many small achievements for their game if they wish. But really, none of this matters because Steam achievements are easily auto-unlocked via SAM.