It used to be like that, but somehow that has changed. If I buy a net with 5 kilos today, there is always a rotten apple after a short time. The same is true with potatoes. In my childhood, a farmer always came with a horse and cart and brought a load, which was then stored in our cellar, enough for the whole winter.

Yes, because the varieties you get at the grocery store are varieties that are optimized for profit. That means fast growing and sturdy enough to withstand the insane logistics of modern supply chains. Taste, shelf life and nutrition all come later. Buying veggies that aren't grown in greenhouses year-round off-season also means that by the time you pick it up at the store, it might have been in storage for months already.

Try getting in-season heirloom varieties at a local farmer's market. The result will be very different. Sometimes the prices won't even be that different, since a lot of middlemen are cut out.

As a little bonus, you help your local economy, and the person selling to you will be able to tell you what it is you're getting your hands on.