A cool thing to do is to go on a site like GSMArena and follow the battery capacity over time of a particular line of phone (you can adjust for phone weight and volume if you want). It’ll steadily go up.
In 2010 most phone batteries were 1000-1500mAh. Even something like 2000mAh was a huge battery.
In 2015, phone batteries were up to 2500-3000mAh.
In 2020, they were up to 4000-4500mAh. 5000mAh was considered a big battery.
Now, we are commonly seeing 5000-5500mAh batteries in mainstream phones, enabling most phones to get 12-14 hours of battery life (when new).