If you’re serious, it’s because (in the US at least) they often don’t have to ship nearly as far, and no one cares what they look like. Many (by no means all) are processed nearby to major tomato producing regions, and are processed when actually ripe. Store tomatoes are normally unripe, gassed to look ripe, and shipped. That way they look good to the eye, and are firm and damage resistant. They TASTE like watery paste, but a lot of people are now trained to consider that normal.
I get a bushel or so of ripe tomatoes in season from my MiL - which I eat a ton of, and dehydrate and/or sauce and freeze the rest. Every once in a while, I crave a ‘fresh’ tomato during the off months, and in a triumph of hope over experience, find myself disappointed with the results.
IME, other than the three weeks garden tomatoes are available, the options are to use canned tomatoes or to have a home hydroponic garden large enough to allow continual harvest.