there are so many much more richer persons/families not taken into consideration by forbes. russians, chinese, indians, non americans. People that have money spread across borders..
there is no such thing as the officially "Worlds third richest person"... some are "unkown (by forbes)" trillionaires that are not accounted because there are no official records
The only person I could even speculate with that sort of wealth could be Vladimir Putin, if you argued he is a dictator and so controls the entire Russian economy / wealth base.
The consolidation of power is what we have to look out for. So the qualifier to your statement is “yet”. Would you have said the same thing of Putin after he returned to being president? How long did it take him to control as much as he has?
What it doesn't include are people where their wealth is hidden because it was either acquired and/or held illegally and those who have control over wealth but only by virtue of their position (so a king is "rich" because they can control what the sovereign fund invests in but they don't make the list because if they weren't king all of that wealth would be inaccessible to them.) If Czar Putin suffers the same fate as the Czar Nicolas where the people decide it is no longer in their best interest to have him plundering the country then Putin will likely die with greatly reduced wealth, much like Emelda Marcos.
Crime bosses have the same problem, their wealth is a function of their black market operations and when they are deposed or killed the organization reclaims the wealth for itself.
The people on the Forbes list have full control of their assets and nobody is going to rise up in revolution if they decide to spend it poorly. So they are indeed rich 'persons' as opposed to simply stewarding great wealth.