This woman ought to be very proud of herself. She's almost sold out of her tomatoes and look how many that shop still has in stock. There must be hundreds. She's taken a major retailer on head to head, at an increased price, and beaten them. She must have a great sales technique. Either that or Ghana tomatoes are just a lot better than European tomatoes.
The comment we think Haderer is making is that there comes a time when too much of something becomes an issue. If you flood the world with European tomatoes at unbeatable prices, then everybody else is out of the tomato game because they can't make any money. It no longer matters if your tomatoes are better than theirs, they're cheaper so they win. Variety is the spice of life - or, in this case, the spiced tomato of life.