A lot of knowledgeable beeks learned this the hard way. Thanks to them, maybe some of us beginners can learn from their experience. Until reading threads on this forum, I would have just assumed the bees would move over a couple of inches to where there was food. But thanks to the old-timers... (Not necessarily implying age factor) I have learned the bees cluster near the center of the hive and move straight up, not necessarily to the side. Which tells me, they need adequate stores directly above the center of the hive, in both stored honey and as added protection, supplying them with sugar directly on top of that, so as they move up, there is food for them.
Don't give up and feel defeated... The best lessons sometimes hurt the worst.