There’s a history of actual usage among some subsets of people, not for everyone. Regardless, it doesn’t really matter if there’s history as long as usage is in fact changing. “Literally” meant one thing much longer than it has been a superlative.
See! Actual usage! The sky is now green.
The only reason people say that Llama 2 is open source is because they have been misled, not because the definition is changing. There's a lot of goodwill around the term "open source" because of its actual meaning, so it will always be tempting to abuse it for your own benefit, as not everyone bothers to check whether your claims are actually true.