It’s a bit more complicated: In your example, if someone from the outgroup (e.g. a liberal person or in general someone who isn’t as mindless and as purely driven by hedonism) suggests that “they” should prefer a different coffee chain, they’ll dig in and go to Starbucks even more because by doing that, you gave them another tool to feel like they’re rebelling against the “elites”, i.e. going to Starbucks went from something they did because they were uneducated to a new source of their personal and group identity. There’s no easy solution to bring people to live in their own best interest when they are so adamant to make every little aspect of their lifestyle into a culture war battleground. It’s exactly as hard and prone to fail, as getting people out of a cult.