Having worked for a county in California for 13 years, I have to call BS on your interpretation of the meaningless data that you presented.
Nobody there is working for base salary. Even raw recruits are given a 5% raise after six months, and again, after 18 months, 30 months, 42 months, 54 months, and 66 months.
Also, working hours rules cause all pay to jump up to overtime rates after working an extra shift, until a regular break occurs. (that can be a week!)
California firefighters also get to retire with big pensions. Paid for by taxpayers who don’t have pensions of their own.