Consumption taxes in practice are incredibly regressive. Someone who earns $20,000 must spend the majority of their money in order to live. Someone who earns $1.2 million will probably spend a small fraction of it.
There are billionaires that live in modest homes and don't particularly act or spend like their rich, but they enjoy all of societies benefits that created an environment that enabled them to become rich. They should pay for it so that future billionaires and millionaires can be made.
15% tax rate applied at point of sale universally. Say $20K in spending per person is exempt. Each person receives rebate (or prebate) check for $3K.
You end up with a progressive consumption tax.