IMHO its more about the varieties that are grown for industrial scale and efficiency, rather than flavor. I was part of a community garden and started a lot of stuff from seed- celery, tomatoes, onions, garlic, lettuces etc... and I was overwhelmed by the different numbers of varieties of each and that "celery" isn't just celery. To be fair, not all of it was better- the celery variety was very bitter and chewy, but most other stuff was much more flavorful, though yields were smaller in most cases. The lettuce we grew in particular was so much better than anything sold in a store- at a cost of the fact that it would be wilted and almost unusable by the next day. We did throw in some garlic bulbs straight from the super market to grow next to our "heirloom" variety and the supermarket garlic was exactly what we were used to, while the heirloom was much stronger, and arguably more pleasant (I love garlic). Cooks often joke that "one clove" of garlic really means 5 to them, and I wonder if this is more of a result of breeding garlic over the years for different qualities other than its garlicky-ness instead of just recipe writers with a light hand... I don't think its the methods being used in large scale farming, but really more the varieties attempting to be grown.
There is also a factor that some types of foods will degrade within hours to some extent of being picked- Herbs I pick out of my garden like thyme and rosemary are extremely fragrant when picked, even a few hours later they are noticeably less so. I think many consumers have picked up on this, over the last decade or so I have noticed the fresh plants section of the grocery store expanding, while the "cut and plastic boxed" section of the store shrinking. I am in an urban area, most people don't have outdoor space (I didn't for many years), and I had difficulty keeping those plants alive when attempting to keep them going on my windowsill with a western exposure.