The vast majority of those circuits are sleeping pretty much all the time. However as you get older your battery keeps up.. except those challenging times when you activate too many things. Like say nav (that runs the GPS, GPU, 3D chip, CPU, radio, compass, etc). Then the phone just turns off because there's not enough voltage.
Many people complain about "crashing" phones, claiming less reliability over time. Seems like often it's just the battery that can't manage the needed number of volts under load. You can witness this when ever less intensive things crash, but they all work if you are plugged in.
The sad thing is that these new top of the line smart phones could be useful for 5-10 years. Fit/finish with glass/aluminum, top spec CPU/RAM, expandable storage, etc. Sadly the epoxied battery reduces the practical life to 2-3 years.
In what world would a modular/expandable phone (like has been attempted several times) decide you might want to add fancy speakers, fancy camera, 3d vision, etc. But STILL expoxy in the battery? WTF?
I wish the government would stem in and just mandate that phones have user replaceable batteries to keep them from just filling the landfills after a few years.