The book is exactly the opposite of this. The Principles chapter alone talk about many things that involve actually dealing with numbers (SLO, measuring complexity, etc).
Unless they are testing correlations between these target metrics and business success or some other external cost metric, it’s still “just feels”.
I’ve seen internal crusades against cyclomatic complexity that resulted in massive engineering waste to reduce and reliability saw no improvement.
Pager goes off! Grab pixel. Press finger print reader until it lets me enter my passcode. Ack page. Put down whisky. Shake self. 5 minutes to be logged in and dealing with the problem.
Password. gnubby. password. gnubby. gnubby. gnubby.
Check alert, see playbook, ignore playbook. Check which cell the problem is in. Correlate with rollouts. See a match. Roll back poorly tested dev promo project. Charts recover. Alert not firing.
Log out. Back to whisky.
It's the equivalent of saying "SWE just adds new stubby endpoints to a service, so simple".
When you’re being paged for the Nth time because of an idiotic problem that you’ve pointed out repeatedly, you too might exhibit these traits.