Why did Toyota create two brands model with similar product, Harrier and Lexus

$$$$$$$$

Many companies do that.Ford and Mecury,GMC and Chevy.
It is just a way to add more options to one chassis,and it keeps assembly line layouts standard.
Ford did it with the Fox body,and many companies will be doing it more very soon.

Lexus is not Toyota. Lexus is by themselfs AND THEY DID IT FOR MONEY

Toyota is the parent company and Lexus was originally created for the US market where there was a great demand for luxury vehicles. The company then began to introduce the vehicle in other countries under the Toyota name. Today however that has change. All of the Lexus vehicles will now be branded Lexus and carry the same names worldwide. You may see different engine sizes available in other markets with different features, but the overall vehicles will now be the same.

It is all about social status & economy of scale. For example,

Toyota Harrier - comes with 2.4L & 3.0L engines. Fabric seats. Leather, Traction control, Sunroof - all optional. (Cheaper)

Lexus RX330 - comes with 3.3L engine, full option. (Cost More)

So if u can afford more, u go with the better brand. If not, go with Toyota.

But both cars comes out from the same factory.

Like offering different trim levels in other cars, only this case, even the brands r different.