> But the types and structures of electric car and mobile phone batteries are not the same. Car batteries are designed to last far longer.

What prevents the same advancements from being applied to phone batteries?

Phones don’t have active cooling, or just proper cooling. Heavy usage and charging will heat up the battery a lot. A warm battery at a high state of charge will deteriorate fast.

Also, they aren’t designed to last very long. One manufacturer could reduce the max voltage in the BMS (battery management system), or reduce the charging speed at high states of charges, to significantly increase the lifetime of the battery but they somehow don’t. Though you start to see some phone limiting their charge.

Battery degradation isn't really a function of use as much as its a function of abuse.

Phone's are designed to drive their batteries hard. If you are gentle about charging it slowly and keeping it in the 30-80% state of charge region it will last a long time.

The worst thing you can do is aggressively charge it to full and drain it till dead constantly. It will last a few hundred cycles before it gets seriously degraded.

A lot of people unfortunately (fortunate for smartphone companies) do exactly that (you know that person in your life who's phone is always dead?).

Phone batteries are cheaper so less motive to invest in changing the supply chains for a different design.

Planned Obsolescence.