Why is being late normalized?

Since little, my mother always taught me to be early to literally anything. School, appointments, practices, events, you name it. She would always take me places 20 minutes early or around that. Im a senior in high school and Ive noticed honestly how late a manority of students arrive to school. I understand there’s some obstacles that get in the way for people but i’ve also noticed with my friends when we hangout, there are times when they may be a little late. Or even when im at school, I text my friends if they are coming and they say “yeah im on my way” only to show up last minutes of my first period class. At this point I know who doesn’t show up in the morning. Im not complaining about being late but I wonder if this is something else people notice too🤷‍♀️ How often do you see people late at work or school?