Thousands of federal judges have served a lifetime tenure. Less than 10 judges have been removed from office for bad behavior over the last 219 years.
There is no term limit on Article III judgeships.
“The Judges, both of the supreme and inferior Courts, shall hold their Offices during good Behavior” U.S. Const. art III
Your statements dismiss as surplusage the conditions which qualify tenure.
> Less than 10 judges have been removed
So what? It does not change the rule, the rule which you dismiss.