Good survey of the decline of the Roman Empire.

As to Elon Musk buying Twitter for 44 billion dollars, I read an interesting article this morning in the New York Times on the Twitter takeover. Musk actually coming up with the money for the purchase is not a done deal. If you look at the Twitter stock price (48 to Musk's 54 purchase price) Mr. Market still has some doubts that the deal will go through.

I also looked at the options activity - there are more call options betting that the deal will go through, but there are also lots of put options betting on a failure. So there is a lot of uncertainty.

If the deal collapses it will cost Musk a billion dollars, but that's a lot less than what may happen to his fortune if he actually purchases Twitter.

The reason that the Twitter board agreed to the takeover is that they could not justify refusing, given the offer. Twitter is, at best, thinly profitable. While Facebook throws off vast amounts of cash from advertising, Twitter can barely pay their expenses.