As a person who invested during the tech bubble, I can tell you that stock can also be bought on margins. Most tech companies has a 50% margin requirement.

So a stock holder can buy $100 worth of stock with $50 and carry the rest $50 with a loan of about 7%. If the stock drop to $50, he has a choice of either pay up the $50 and still hold the stock or sell the stock and got nothing for it.

The only difference between tech and RE bubble is the size of the leverage. In stock, you got a 1 to 2 leverage (50% margin). In RE, the leverage before all the easy credit was 1 to 5 (20% down) but now with all the new creative financing, the leverage is 1 to infinity (0% down and no closing cost).

Also the carrying cost is different. You can do the math.