you have no idea why some things do well one year,
and others do poorly.
If I were a farmer, then I'd be spending all of my free hours educating myself on how to grow a good crop, each year. But, as just a lowly, kitchen garden-keeper, my free time has to be divided amongst a variety of subjects.
Therefore, I have no idea why the raspberries did so well this year, but the blueberries, so poorly. It could have been the weather at the time of pollination. Or it could be the abundance of rain showers we've had in June this year. Or perhaps, raspberries like our yard better than blueberries.
Whatever caused the disparity between the two harvests, it may have been out of my hands.
All I can do is give thanks and enjoy what I've been given. And maybe make an extra jar or two of raspberry jam, in case, next year, the harvest amounts are reversed, and we receive a pitiful raspberry crop and an abundant blueberry one.