The amount of actual lines of code written by an average SWE at a BigCorp is miniscule. The amount of churn and spinning and hand wringing that goes into that code is staggering. But it's like that for a reason. There's just a lot of people.
It's torture, and in order to maintain productivity you need to have about 5-6 of these processes running concurrently, and it's why you get paid a lot of money to do it.
Do poorly at juggling that and making "progress"? Find yourself on the receiving end of a performance review where the label "meets expectations" actually means "you better start kicking ass at this, or you'll find yourself with no stock refresh grants for next year."
All the money and free food and so on is just a salve to try to make the whole thing less unpleasant. Some people get a high out of the process, while it drives other people slowly crazy.
(In my last months at Google the only part of the job I "enjoyed" was the week I was on-call for the first time on my new team. Because it was the only time in over a year where I felt useful even though it was quite stressful. That's how I knew it was time to pack it in)
I wouldn't recommend it though since it's soul crushing.
They don't have it easy either. They have to demonstrate at least once a year that they've "accomplished" something in spite of an entire organization of gates that make accomplishing anything nearly impossible. But they still have to figure out a way to do it, and it still has to be somehow represent enough to justify their pay.