The incoming Q1 earning reports will show if these actions are mainstream enough to make a visible dent in companies quarterly earnings. For now, the already reported Tesla sales numbers in Europe are substantially down, but Tesla is the strongest target of the boycott. It will be interesting to see if consumer companies such as Coca Cola, Nike, Amazon also report a substantial drop in EU sales.
Not sure how much it gets consumed, but many places in Germany rather sell Fritz-Kola only.
Additionally there are a few that cater to certain groups with special products like mate soda (Loscher invented it with Club Mate I guess, but nowadays there are 10 big brands and a few small ones) and special kinds of cola like AfriCola or Mate Cola. Fritz-Kola is one of those products, you can get it in every city in well-stocked supermarkets, but it is a product that only caters to a certain kind of people and establishments (think "Berlin-like club-going techno-mad party-crowd" maybe). So many places will carry something else that caters to their group, and their region.
That is also why the Coca-Cola marketshare that the sister comment mentioned will go down, but it will not be replaced by another big producer, just maybe a handful of nationwide brands plus tons of regional ones.