[vectorEQ]

if the learning/enjoyment/motivation curve flattens you have choices.

either accept it and settle at an employer, or change jobs. often this happens around 5-6 years in if not sooner.

its ok to settle at an employer and just be happy wiht your life. if it sucks the life out of you i'd suggest finding a new challenge. with a resume of longer term employment at a big corporate like google , finding a new challenge should be doable.

perhaps you enjoy a startup, its a lot more dynamic and versatile, though often pays less atleast initially. personally i hate that, and try to challenge myself in my current work rather than looking for different jobs. but then again i don't have issues with my job being a bit boring / stale as i try to find things outside of work to fufill me which can also help a lot to fight depression / stress etc.

in the end you sound like you need some thing you are passionate about to work on to feel good about yourself, this is normal, but it doesn't have to be your job which gives you this.