I do think this question has been asked at least once before. But I will try an answer again.

Here in China, almost all land used in growing vegetables is depleted of the nutritional elements after years of use and hardly any fertilizers applied. That could be a reason for bland tomatoes. Other reasons could be because they are picked green, before sugars in tomatoes have a chance to develop, and thus the "no-taste" to them. If stored in coolers before brought to the market place, that ruins the tomato flavor, once refrigerated they will never taste the same. And once ready for the market place, if gassed to ripen, the texture and flavor will not be the same.

Maybe this is why I do have a few 5 gallon plastic buckets filled with soil. I do punch a few holes on the sides and bottom, fill them up with good soil, and plant tomato seeds on top, sides and bottom. I hang bucket close to my balcony ceiling, and water and fertilize them as needed, allow them to rippen on the vine, and I do get good tasting tomatoes each year, besides enjoying to see them grow on those hanging vines.

Lack of preservatives....

I think its the variety type also, they aren't beef steak tomatoes, a large  meaty sweet variety.

To match their personalities.... (bwahahahahaaa..... ok, just kidding.. )

Part of it is that it's not a Chinese fruit. So the growing conditions may not be best suited.

Plants in different places are different .