That strip of land in North Dallas, Richardson, and Plano was/is way too dependent on Telecom. The stocks for these companies has been in a free fall for the last 2 years and is not necessarily related to the latest stock market downturn. Telecom suckage is reflected more in the precipitous drop in the Nasdaq, from the high of 5000, rather than the Dow or S&P.
I personally don't think the Stock Market crash of '29 was the cause of the Depression - just a rather visible clue that something wasn't right with the economy. The root cause is probably more tied to the destruction of European economies in WWI and the collapse of world trade.