I remember, long ago, a state supreme court ruled that the legislature was not providing enough funding for the court to do its (state?) Constitutionally required duties. The court ruled that the legislature must provide it with more money.
Court funding is a separate issue from funding for the rest of government.
In any event a simple majority vote of the House and Senate can abolish entire federal courts or groups of federal courts—and it is happened several other times in our history.
These judges may not see it coming until it is too late.