Nothing wrong with decreasing population, but when your richest citizens are leaving, and poor migrants are coming in, then you start having fiscal problems, particularly for a state that has decided to fund itself with income and sales taxes rather than property taxes.
Another reason why property tax is a more stable funding source -- unlike income, you can't take it with you. There is a whole list of reforms that California needs to undertake to recognize the new reality it's in, and shifting itself to being funded primarily by property taxes is one of the biggest necessary changes. The second biggest change is significantly scaling back spending and decreasing its vast administrative bureaucracies.
A "majority" of any sizeable group is not going to be rich. What is important for fiscal impact is that the rich are leaving, not that other people are also leaving.
If you want to see data, we can look at IRS data:
"New York’s tax base shrank by $19.5 billion while California lost $17.8 billion as a result of workers fleeing those states during a time when lockdown measures allowed employees to work remotely, according to the Wall Street Journal.
Other high-tax jurisdictions such as Illinois ($8.5 billion); Massachusetts ($2.6 billion); New Jersey ($2.3 billion); and Maryland ($1.9 billion) also saw an exodus of workers during 2020.
The states that reaped the benefits of the “wealth migration” include Florida, which gained an additional $23.7 billion in gross income; Texas, which gained $6.3 billion; Arizona, which took in $4.8 billion more; North Carolina ($3.8 billion); South Carolina ($3.6 billion); and Tennessee ($2.6 billion)."[1]
Ending Prop 13 would not cause "significantly scaling back spending and decreasing its vast administrative bureaucracies." Instead it would have the opposite effect. All other taxes would stay the same, but now they'd have this additional source of money.
This may be difficult to understand, and I can accept if you refuse to believe it, but it's possible to say that two steps are needed without the first step also accomplishing the second.
"e.g. 1) switch to more funding on property taxes and 2) reduce administrative bloat"
Shockingly, this does not make the two steps "self-contradictory".
I mean, how do you communicate with someone that has no ability to make quantitative estimates? Yes, getting rid of prop 13 would require the administrative complexity of one specific job of one department to increase. No, this does not contradict the goal of reducing administrative waste. Fire a million bureaucrats (15% of the population of California works for state and local government), shut down 20 departments, and the 1000 people you need to hire for prop 13 rollback will not reduce the overall goal.
And by shifting responsibilities, you could easily do this without hiring anyone else - almost all states have a value-based property tax system, and this includes states with extremely lean administrative load compared to California, so your claim that following their model is some self-contradictory nut to crack is specious.
Another reason why property tax is a more stable funding source -- unlike income, you can't take it with you. There is a whole list of reforms that California needs to undertake to recognize the new reality it's in, and shifting itself to being funded primarily by property taxes is one of the biggest necessary changes. The second biggest change is significantly scaling back spending and decreasing its vast administrative bureaucracies.