What is conservatorship? Who gets conserved?
A conservatorship is when a judge rules that a person is not competent to care for themselves or manage their own affairs, and will not be competent any time in the near future. People cannot be put on conservatorship because they're on drugs, going through a bad patch or having a breakdown, or have a treatable disorder like severe depression. People get put under conservatorship because they have severe, long-term or incurable disorders, like disabling brain injuries, degenerative diseases of the brain like dementia, are too developmentally delayed to be independent, or have severe, disabling, long-term mental illnesses like schizophrenia. The legal criteria for putting a person under conservatorship are very strict, and no honest judge would put a person under conservatorship just because they'd been on drugs or had a public breakdown.
Now it has long been rumored that Britney's main problem is bipolar disorder, and most people with bipolar disorder are not under conservatorship. If they are rational part of the time or able to stay completely rational with the right medications, they are legally free to make their own decisions - including the decision to stop taking medication and ruin their lives when the next manic or depressive episode hits. So that's the big question regarding Britney - is her bipolar disorder really so severe that she's unable to run her own life? (Yes, some cases are that severe.) Or are does she have health issues in addition to the bipolar disorder that make her incompetent, or have the judges overstepped their authority? Because it's pretty unlikely that she's just better, none of the conditions that can get a person conserved are likely to get better.
So this isn't really my field or anything, I'm not a professional conservator or a lawyer, but since I seem to know more about conservation than most people on this board... so what the hell.