> There are five known fundamental tastes in the human palate: salty, sweet, sour, bitter, and umami.
I always hate when folks call savoury 'umami' instead. We already have a perfectly good word in English for the taste; we don't need to add a new one!
> And so he turned to ketchup, because, alone among the condiments on the table, ketchup could deliver sweet and sour and salty and bitter and umami, all at once.
I'm pretty sure A1 & HP deliver much the same effect. Even Worcestershire sauce does.
Finally, and most importantly: there's a much simpler reason for the failure of World's Best Ketchup to take over the market: no-one is likely to trust a product named 'World's Best' to actually be the best. Grey Poupon seems to come from France, with its name & packaging: one is tempted to believe that it's an ancient brand, one which might well be excellent — or even the world's best. But World's Best Ketchup is clearly new, and there's no particular reason for me to believe it's actually all that good. It could have just been invented by some team of accountants in a conference room at the Holiday Inn.
Never mind that Grey Poupon isn't actually French. Never mind that Jim Wigon really seems to love his ketchup. The vast majority of folks don't know those facts.