I'm not so sure the 30% pay increase with every job hop is necessarily the norm either. Maybe at first when you're moving up from entry-level to senior. But in some markets, you hit the regional salary cap after four of those and you're stuck with 2-4% annual raises -- even with in-demand skill sets.

If I posted the job offers I've received for having experience with Spark/Hadoop, building / productionizing machine learning models (since 2011 even), an AWS certificate, and 15 years worth of other worthwhile skills, people here wouldn't believe me because they are so low. Definitely well below the startng salary of someone at Google. Yet I've had three, all of which were basically identical.