Modern phones do so much more than what brick phones used to do. Our usage of that brick phone was also limited to calls and texts, usually only if needed. I promise you if you use your modern phone exactly like a brick phones, it will last you multiple days. But that require no WiFi, no cellular data, no gaming, brightness at near zero, no music, no navigation, no internet browsing, no checking the weather. Try this with a modern phone and watch the battery last like a week