Column spline failures due to lack of maintenance or the use of unsafe drop brackets have killed a number of people.
Is the steering column a maintainable item? I've never touched mine. Should I have done?
Depends on your definition of 'maintainable', I guess.
They certainly are rebuildable and that's all I ever do with them, top and bottom bushes as well as an overall clean & paint.
The one item though - for me - is a daily check when off road is the nut on the steering wheel. It does work loose, but is only a 10 second job to re-tighten.