Doesn’t really make sense even to users. They would shrink the battery to a small fraction of its original side, market it as the world’s lightest and thinnest phone, with 4x the battery life of a normal phone. Then they’d have some other products of a bigger battery version for emergency red phones.

Beyond just companies wanting to turn a buck, there’s other more obvious limitations. The bands to communicate with the tower require physical antennas inside the phone and those frequencies are recycled over time to different protocols or sometimes different uses entirely. It would be useless as a phone before it’s dead.

Also the whole thing about energy density. Current lithium ballpark density is 250 Wh per kg. Taking a modern galaxy 5000mah (19.4wh) battery and multiplying it by your chosen ratio of 10 hours vs a hypothetical 876000 makes it 21,900,000Wh per Kg, still less dense than fusion energy, which is around 24,000,000,000Wh per kg but very close to fission energy density, which is around 24,000,000 Wh. Of the Uranium that actually fissioned during the Little Boy bomb explosion, it only amounted to about 0.8763kg, less energy than a kilogram of your hypothetical battery. I guess luckily batteries only weigh about 50 grams? The factory making them would have more bomb potential than the Beirut explosion if they had more than 47.5 kg of batteries, or enough to make 950 phones.

As an aside, I can’t believe how big the Beirut explosion was, 1GWh. Insane and horrifying.