Don't people just sample the market to find out a brand that is to their tastes (performs as desired) and then keep buying it while the price is still of value?
There are a lot of theories, but, the one thing that has been consistent for at least the last 60 years, is that if you have a consumer Brand of something, say "Tide Detergent" - and you stop all your brand advertising in a certain region, sales go down in that region, and when you start advertising again, sales go back up.
Price, Value, Placement, and, obviously, competition are all conflating factors as well - but the underlying response to advertising has been pretty consistent.
I've always wondered what the marketing campaigns look like for the 100 different brandings of the same product at the grocery store. Do Toothpaste A and Toothpaste Z340 target completely different demographics, or are they going for the same eyeballs with their ads?
Price, Value, Placement, and, obviously, competition are all conflating factors as well - but the underlying response to advertising has been pretty consistent.