If there's a decrease in both protein and fibre, what is there an increase of to compensate for it? There has to be "more" of something per unit of mass.
0: http://www.redorbit.com/news/science/1112648268/scientists-f...
If buying from farmers (not distributors) at your farmers market then those tomatoes were most likely ripened in the field then picked rather than gassed which is why they taste much better.
What you get in grocery stores is a green tomato that has been gassed so the flavor isn't the same as truly ripe tomato. Also, the varieties planted that are good for mass productions, packing and shipping aren't necessarily the best tasting varieties.