The story with tomatoes is largely a mixed bag.
Outfits like Escalon and Stanislaus sell primarily to the foodservice industry so there is little incentive for them to secure sources of organic tomatoes for processing, since this would raise their prices charged to customers, who could care less about organic tomatoes. Muir Glen is perhaps the largest domestic supplier of canned organic tomatoes. In my view, their tomatoes are better than most of the other tomatoes sold in supermarkets. But, if you don't care for their organic tomatoes, and you don't live near local farmers that farm organically, then your only really viable alternative is to grow your own. When I lived in places with good soil, this is what I did. However, even at that, the organic tomatoes I grew, as good as they were, would not have naturally produced a sauce as sweet as the 6-in-1. The closest I have come to the sweetness of the 6-in-1 tomatoes in a can is yellow, low-acid Roma tomatoes. They are good on pizzas but almost impossible to find. The small, fesh cherry-size grape tomatoes sold in supermarkets come a close second in sweetness. They are also good on pizzas--better than most fresh tomatoes.
I ultimately discovered the San Marzano tomatoes. They were rarely sold in the supermarkets, including the upscale specialty markets. So I had to find mail order sources. Many people deem the San Marzano tomatoes to be sweet. They aren't. What they are is low-acid. They are also pulpy with few seeds and make good sauces, which makes them appealing for use on pizzas, and particularly so if you want to try to replicate authentic Neapolitan DOC pizzas. Along the way, I discovered that there were genuine San Marzano tomatoes (the varietal) and knock-offs. One such knock-off is San Marzano tomatoes grown in the U.S. from San Marzano seeds. In Italy, the genuine San Marzano tomatoes are grown on volcanic soil, a condition that cannot be easily replicated elsewhere.
One can of the knock-off San Marzano tomatoes I bought (distributed by SILtd. in NJ) showed pictures of San Marzano tomatoes all around the label along with the words "Pomidori Pelati". To my horror, they were tough and tasteless and may well have been the worst canned tomatoes I ever tasted. I still use and like San Marzano tomatoes, but I am more careful in scrutinizing labels to be sure that I am getting the genuine article (mainly DOP San Marzanos). But even the best of the genuine San Marzano tomatoes, of which I have tried many brands, aren't as good as the 6-in-1, IMHO. Until someone can lead me to something better, I see no reason to try any others (except that I will still use the real San Marzanos from time to time for my Neapolitan style pizzas.)