Philosophically, spiritually, or both?

Many people are either too invested in their own religious beliefs or don't think that Buddhism can be true. There are also a group of people who haven't yet heard enough of Buddhism. These people may or may not convert to Buddhism, which is why it's so fast-growing. There are also yet another group of people who are Buddhist, but are not allowed to publicly say this due to laws.

Because some people don't want to be Buddhist. Some people believe in other things and don't think that Buddhists are right in there ways so they follow a different religion/belief.

Why is the world no all Atheist?

Why is the world not all Theist?

Why is the world not all Satanist, Christian, Good, Bad, Black, White?

Simply put, people have their differences. If there was but one person type on the planet, not much would get done.

Duplicate

I would argue that the world is in fact Buddhist. Whether they call their faith or process Buddhism or not the experience of suffering and overcome suffering is Buddhist by nature.

You can see Buddhism being embraced in almost every walk of life be it yoga or atheist solutions to problems / suffering, psychology, self help books. They may not call it Buddhism but they are most certainly are Buddhist principles repackaged in other forms.

Same question could be asked of any religion or philosophy. The answer is the same for all of them. The answer is the same as the first sentence in this post.

Buddhism is a spin-off from Hinduism. Every now and then, a new guy pops up claiming to be the latest messenger of whatever it is behind Buddhism (in Start Trekking, it's "The Force"). Baha'i founded by Bahá'u'lláh claims to be an improvement of Buddism with a supposedly new and improved "prophet". Buddhism is a thing of the past.

The promise of Buddhism is a lie, fooling people into believing death exonerates them of their sins so they can't be punished by it and left to fry like eternal sausages in Hell.