Your reasoning is very pedestrian!!!
Very few people EVER get rich doing one thing only ("alone")!!!
Even in real estate, I can't just show up and demand for land! I have to do some other sh!t to make the money to buy land. Once I buy the land, I will most probably not sell it at a profit or develop it immediately. That means I will have to do more sh!t to buy more land or develop the one I have!!
And for your information, most wazuans (you not included of course) don't do
only one thing!! Most own more land than you will ever own, are in stocks, have businesses, do some consultancy on the side etc. etc. And they don't go round shouting about it and imagining anyone not in their line of business will never make money!!!
Never count on making a good sale. Have the purchase price be so attractive that even a mediocre sale gives good returns.