That's a good point; and since you mention it, I was amazed just a few weeks ago when I took my phone apart and saw a small PCB with only a few SoCs, power ICs,

That's a good point; and since you mention it, I was amazed just a few weeks ago when I took my phone apart and saw a small PCB with only a few SoCs, power ICs, buttons, and a bog-standard 3.7V 2200mAh LiPo battery. I don't know what I was expecting, but it was still sort of neat to see.