Although it's more pleasant, you don't need water vapor for good vaping. Moist weed isn't better or stronger. The moisture just gets vaped first and once the weed is dry, you're right where you are with your old, dried out supply. Weed loses potency over time and you may be experiencing that. You'll also develop some tolerance when you use the same stuff for an extended period. There have been times when I've used the same supply for a long time, then tried some different, but inferior weed, and gotten a better high from it, at least initially.