It's the opposite. Frontends are statefull (backends are often also), but frontends don't deal with long living data. Everytime the app/site is reloaded/restart

It's the opposite. Frontends are statefull (backends are often also), but frontends don't deal with long living data. Everytime the app/site is reloaded/restarted, it starts with a fresh state. Backend however often has accumulated a lot of data tech debt over the time.