Moving to the US from Europe the quality of the produce was one of my biggest culture shocks. There was tons more availability especially out of season and it was cheaper but the fruit and vegetables here are so bland. Even the so called heirloom varieties are devoid of the flavor I’m used to.
It’s gotten better over the years as consumer awareness has grown but now there’s the trend of making fruit increasingly sweet like cosmic crisp apples, sumo mandarins, or cotton candy grapes.
Part of it is that the plants have been optimized for durability in transport, harvesting etc not just flavor. Farmers Markets here in the US or smaller chains are more likely to have the better produce but not guaranteed depending on where you are.
Turns out you can measure the sweetness of an orange using an infrared light and camera.
Then you can sort all the oranges by sweetness, and sell the sweet ones to one place and the pretty ones to another.
Where the consumer only sees the looks in the shop, why send that country the nice tasting ones?
This sounds like a business opportunity. Handheld produce analyzers you bring to the store/farmer's market/etc.
Out of season stuff is usually imported from Mexico or South America. I'm guessing the long distance transport conditions may change the taste of the produce?
Yes, everything from parts of the fruit not rippening (Sometimes not at all), weakening of flavours, or visually ripe fruit that's really not
Having scaled the latitudes of Europe, I will say that your generalisation is moot.
Try an aubergine in Germany, and then try one in Sicily. The difference is stark.
My point of reference is the same latitude as Moscow for what it’s worth and yet the food I get here in Southern California falls short. Sicily would be a dream in comparison.