I acquired this album (贺 - 中国邮票 2007) sometime back and was tidying it together with the rest of my stamps. It struck me while I was flipping through the pages that the China album has a lot more stamps issues than Singapore mere 10+ issues per year.
It is also interesting to see that countries do go through somewhat similar path in development. The reason I said that is because from this set of Postal Saving Bank of China stamps, I see the Singapore POSB equivalent. Both saving banks started as a branch department of the postal agencies, simply because it was convenient for people to deposit saving money when they conduct their frequent visits to the post office. Given the less frequent travels to the post office, this habit died.
Given the rich cultural history of China, it is no wonder that they have more issues where artists can express their creativity. Of course, the larger population of stamp collectors properly helps a lot too.
Similarly, they have stamps with nation building theme in mind, e.g. this set of stamps commemorate their 17th National Congress. There are a lot more different stamps sets in the Chinese album but I guess a smaller number of stamps issues in Singapore's case properly also help to reduce the cost of stamps collecting, which is important to encourage the take up of stamp collecting as a hobby.