In this sense the word is obsolete; so is that kind of government.
If we used 'em all the time they wouldn't get obsolete, would they?
Wheelwrighting is fast becoming an obsolete art in the North.
Nothing can be obsolete that is of divine institution, your Eminence.
Fortunately, this type was not used extensively, and the battery is obsolete.
But woman as a human incubator ...