If you are "unaware of any professors that do nothing" you are not paying attention. Or perhaps you are one of those individuals who is benefiting and therefore do not see your complicity in the whole matter.  I am sure that there are many who have "pride and a love of their fields drives them all to achieve and succeed to the limit of their abilities" however, they, I must say are few and far between.  Removing tenure may be our saving grace, perhaps a little more competition may light a fire under those who continue to take advantage of tenure-track and actually do the job they are well compensated for.
I don't agree with your assertion that eliminating tenure "would also be the single greatest contributor to the dumbing down of our society," if that's the case how do you explain our public education system.