Netflix doesn't pay dividends. Had you bought 1000 shares of Netflix for $20,000 three years ago, you would now have over a quarter of a million dollars. That's exactly why people consider buying companies that pay no dividends! They want to grow their investment.
The market makers' job is to create liquidity. HOWEVER, they are not fools! These are professionals who work on Wall Street everyday, and they know the stock market better than 99% of the traders and investors that they do business with. Plus, they have access to the fastest and most advanced information network that shows everything. At any given moment, they can see how many people want to buy XYZ stock at different price leves. They see how many shares are up for sale at once and how many shares have been shorted. They have quite a bit of advantage. Let's put it that way.
They do not buy when everybody sells. That would be foolish. It's a quick way to get killed in the market. What market makers do is they see where people want to trade, and they move the market in the direction of the biggest volume. Market makers have to keep an inventory of shares, so they do own some stock, which they can sell at any time. By selling their inventory, they can create a small downtrend. So, they have some control over the direction of the market (sometimes). Sometimes the market has made up its mind that it wants to go up or down, and in that case, they just let it ride. But if there is no definite trend, they can make a turn and cause a stock to jump up and create an signal for other traders to buy. When other daytraders see the signal and jump on the wagon, market makers may ride the trend for awhile and then get off at some point. Their goal is to create big volume, but at the same time they want to keep their books in balance. They don't want to lose money. And they don't want to own too much of a stock or too little.
If a trader enters an order to sell a billion dollars in the open market, the market makers are going to buy up some of it, of course. But when they see the large supply of stock pushing prices down, they sell their stocks and stand aside to let the thing fall. That's what happened on May 6, 2010. No market maker is foolish enough to buy when everybody is selling.
Why would a market maker buy Enron when it's falling? Keep in mind that market makers make frequent trades. They may buy one one moment and sell few seconds later. It's not like they buy Enron at $50 and sell 1 week later at $20. That's what some investors did. Market makers make lots of trades very quickly. They might buy at $39.50 and sell at 39.62.