These have flopped. Most people who like meat want real meat. Most people who don't like meat don't want fake meat. The remainder is the market for fake meats, and it has proven small.
They flopped as "meat substitutes" because they are not in fact meat substitutes and never were. They are flavored soy protein. They are junk food. Absolutely nothing like lab-grown meat or any other kind of meat, in neither form nor function nor nutritional value.
Impossible patties seem a legitimate meat substitute for those who choose to purchase them.
This isn't some kind of pro-meat screed, either. It's just not true that they are equivalent culinarily or nutritionally. They are a pretty good approximation of beef, but they're not the same.
If the Whoppers seem the same, it's because Whoppers are junk food, and Impossible meat is kind of just vegan junk food.
My guess is that it's a calorically dense nutritionally complete food (if you like eating organs)