With witness votes lasting indefinitely once made, voting for witnesses is one small step we can take to help make a giant leap in favor of the value of Steem.
NO, witness votes can be revoked, shuffled or proxied, they are not indefinite.
#witness-update tag is not the sole tag to look for updates, you should be looking at the main tag #witness-category too.
While being a witness does generate rewards, it's not the only factor in being a witness, like you still preach. Anyone can setup a witness, that doesn't mean anyone should. Would you have setup a witness one year ago when STEEM was worth 6 cents? Of course you wouldn't. Yet the early witnesses kept their engines running at a loss for months, it's a testament that money isn't the only thing that defines a good witness.
When one bails out on Dash too early (and sells their node), missing out on $100ks in profits, then you gotta make money somehow! Human nature ;)