How did Maitreya become so large and rich? The title is not meant to be disrespectful, but only to highlight the incongruity of the representation with what I understand of Buddhism.

Images of Maitreya in English Wikipedia are modest and comtemplative, but the Chinese page shows one familliar image with a large, well-fed body, surrounded by riches, and a big happy grin. Where I live these representations of Maitreya are everywhere.

It is understandable that as buddhism spread to different cultures certain superficial aspects might be altered to convey ideas in different ways. Here I'm just asking about history of the change.

When and where were depictions of the Maitreya buddha first changed so dramatically?

edit: The question Why is Budai often associated with the future Buddha Maitreya? suggests to me that this is not actually a representation of Maitreya at all, which conflicts with what I remember and what a google translation of the Chinese Wikipedia page at least seems to say.

 Source
In Buddhism, the Buddhist statues are essentially the artful and symbolic expressions of the Buddha teachings, with the objective to educate us the meanings and teachings of Buddhism. Therefore, we should see the statues of Buddhism as teaching aids and the cultivation of virtues we aspired to achieve. They are not meant to be statues of gods for worshiping. As we come to realize the inherent meaning of Buddhist symbolism, we will truly appreciate the sophistication and completeness of its educational values.

Maitreya Buddha, or the Laughing Buddha, or the Bu Dai monk (the historical monk figure better known in China), has widely been seen to be portrayed with immense happiness, and its statue is sculpted big in front entrance of a Buddhist temple, and is also sculpted as fat and happy with a big smile and a big belly.

The educational and metaphorical values of the happy and fat imagery of this sculpture is created with profound significance:


The Laughing Buddha is often found at front entrance of a Buddhist temple. This shows that Buddhism greets visitors with a hearty smile, welcoming anyone to come on in.
Buddhism teaches us how to get rid of sorrows and afflictions and attain happiness in our lives. The laughing statue shows visitors coming in to learn Buddhism and follow the Buddha path will attain a happy life. We should also learn to be cheerful and be courteous to all.
Buddhism teaches us to be tolerant and treating everyone fairly and equally. The big belly represents the attitude of inclusiveness, that we take in and be tolerant of anything good and bad we experience and anyone we encounter in our lives.
Some statues portrayed with riches are the artistic representations of our true inner nature of perfect, complete, and infinite treasures (metaphysically) that we all beings by Buddha-nature possess. 


We can see that the above profound significance of the sculpture are actually in sync with what Buddha Sakyamuni has been teaching all of us some 2,500 years ago when he reached enlightened in this world and educated us what he is the path to enlightenment.