VM, I wouldn't be surprised if the WTS either strengthened the nonprofit arrangement or instituted it after that fiasco in Texas. But even the congregation (really the 3 corporate officers selected by the BOE of the congregation that holds the territory the land the KH stands on) doesn't own it nor the corporate officers, only the non-profit corporation. It is not like everyone who gives money to the congregation is buying shares. Since most donations are anonymous, and people are always moving in and out, it would be a nightmare to run it that way besides being illegal under the laws of non-profit corporations. Can the WTS try to bully congregations, emotionally, etc, yes.. As NoApologies says, it protects the local congregation elders (individually) and the WTS from lawsuits as well, since the non-profit corporation is sued and its assets, not the individual JWs.
What the WTS does benefit from is that more affluent congregations routinely send money out of their surplus each month, $500 to $1000 in some congregations I have attended. The other cash flow is from the money voted at assemblies by the elders (without the congregation's input as in the previous example).
Now though if a congregation acts up, the WTS can dissolve it and then would have control over. BTW non-profit incorporation blocks corporate officers from personally benefiting monetarily.
I personally feel the WTS screws over its members more seriously in their policy re child abuse and blood transfusion, things that no dollar amount can be assigned to.
Blondie