Awe this discussion reminds me of the fable of "The Tortoise and the Hare". To build thy massive real estate empire by running quickly involves taking on much more risk and as such you may not reach the finish line if Murphy jumps out the woods and hits you in the knee with a sledge hammer. However, crawling to build it slowly will virtually guarantee you still get to the finish line. I say you fast walk it.
I have read many of Dave Ramsey's books and they are excellent sources of information. Dave Ramsey is really all about teaching you how to minimize risk to reach the finish line. Eliminate debt, save, invest, and give back to the community. To be honest the other guy mentioned in the post I don't know and haven't read his books not to mean I won't. Dave Ramsey lays out a life plan to help ensure you reach the finish line and is built on wisdom in part from his own life mistakes as a real estate investor. I can relate to that and see how that can help many people even non real estate folks. What he also tells you and what a lot of investors don't take into account is that there are other risks outside all the math and the real estate equations that you must assess also. Sure you will have multiple tenants vacate and possibly trash the house, the HVAC need replacing, the roof start leaking, toilet or water heater supply hose burst and flood the house, termites infest and swam the house, lightning hit the tree next to the house and blow out windows, neighbor burn down your fence, tree fall on your house, the bank close your line of credit for no apparent reason, insurance company you have used for years drop all your policies at once without ever having filed a claim. All these things have happened to me.
Then there is the outside risk you can't measure. For instance, you or your love ones get diagnosed with cancer or serious illness, become disabled and need 24hr care, get in a car wreck and get sued, the bank closes your lines of credit (yeah I already said this but this really made me mad with a 780 credit score), the market crashes, you get divorced, a riot or hurricane or earth quake or flood wipes out or damages most your properties, and the list goes on and on.
It is called Murphy's Law and it isn't a matter of if but a matter of when it will happen to you and it is usually when some of those other above property issues happen! Life teaches us these lessons.
So that is why we try to minimize all these risk as much as possible. Eliminate the use of debt as much as possible, saving cash reserves, diversification of investments, math equations, insurance up to the wazoo for everything we can think of (life, disability, long term care, umbrella liability),and among the many of other things of course you need to keep giving back and educating yourself, which is why we post in these forums.