I don't think people choose languages to learn based upon difficulty.
As a side note, Chinese (and English too) has been simplified over time, both in terms of sound and vocabulary, and writing. In the old days, not only did you have up to 9 tones and more consonants, you also had regional variations from village to village. You needed a tremendous understanding of the culture and history to comprehend it all, not to mention any special idioms related. For writing, a standardized system had to be implemented to deal with all the variations, which read like nothing you would speak.
Now today the standard Mandarin has much more simplified tones and vocabulary, and it's written in vernacular. And yet here we are...
As a side note, Chinese (and English too) has been simplified over time, both in terms of sound and vocabulary, and writing. In the old days, not only did you have up to 9 tones and more consonants, you also had regional variations from village to village. You needed a tremendous understanding of the culture and history to comprehend it all, not to mention any special idioms related. For writing, a standardized system had to be implemented to deal with all the variations, which read like nothing you would speak.
Now today the standard Mandarin has much more simplified tones and vocabulary, and it's written in vernacular. And yet here we are...