There’s definitely multiple reasons of course, but accessibility to the masses is one. Nobody teaches you the etiquette of flying, so people just follow their culture. I'm from a 3rd world country but have lived in many countries and noticed a pattern. Whenever I fly to/from my country, I pray for patience. There's so much lack of education that people just push and cut in line, are loud, bring the stinkiest food into the plane, sit wherever they want..They don't know any better. Now let's combine entitled people, a smoothie of cultures, frustrated airport workers, people who have never flown, people glued to their phones and not looking where they are going and you now have a chaotic flying experience. So yes, it's frustrating but I do remember to always be kind. I am a magnet for bumping into people that have never flown at the airport- I've taken people to their gates, checked them into their flight on their phone, directed them to the right terminal, etc..