One day.... battery technology is getting huge investments over the past decade with electric vehicles where more power in less space/weight is critical. Once achieved, it will trickle down to electronics, much like how litium did from NiCD and NiMH did years ago. But I wouldn't expect it until iPhone XX :)

Until then, consider an external battery. Like Apple's Battery Pack that uses the wireless MagSafe to charge:
https://www.apple.com/shop/product/MJWY3AM/A/magsafe-battery-pack