The Oracle of Omaha has long contended that in the long run, simpler, less active portfolios perform better.If 2025 is the year you're first getting into the market, you've picked a wild one to get started. A small number of massive technology companies have soared thanks to their involvement with artificial intelligence (AI), dragging the overall market higher with them.This kind of mania isn't the norm though. And it will unwind sooner or later, deflating most portfolio values when it does.Not every stock ...