I've heard Mrs Claus had a hand in it---she got the whole business, you know, and she's determined to make it profitable.
Rudolph took to drink because Mrs C outsourced the delivery part of their operations to UPS. The eight reindeer were sent to an abattoir...
After she took over, the helpers feared for their jobs (and safety) so they began to organize, but one of her spies ratted them out. Her goons roughed up the agitators, and then she fired the whole lot, replacing them with orphans.
There's some hope, though. The Easter Bunny may buy her out.