Does anyone know why and what the price increase on the MS "Natural Ergonomic 4000 Keyboard went up so much lately and the supply of them went South? They're listed on the MS site for $49.95, but everywhere else online they're $129. I can't imagine it can have anything to to with "the virus". Is it just lack of supply and greed? Are they still making this model? They were about $50 a month or so ago.