Asklemmy

I guess a part is that science seems to meticulously avoid the question "why do we live", in a non-technical way, in a way that actually gives people a sense of meaning.

That and mental inertia, i.e. some things change very slowly.

Humans are tribalistic, like leaders who are assertive and charismatic, like simple answers, are easily swayed by emotions, fall victim to logical fallacies, and a plethora of other things that all work just fine if you're operating on a tribal level as we did for most of human history, or rather prehistory. Now that we are in a different phase of technological growth, which has brought with it massive social change, getting rid of all of that superstitious nonsense is very difficult because of aforementioned characteristics. What were beneficial as it tribal species, and arguably even after that, is now a liability. Or at least more of a hindrance to progress.

Because it's been the way it always has been, because people also hate change, are lazy, and tended to prefer both avoiding cognitive dissidents and minimizing effort to achieve desired results, getting rid of religion is a nightmare hassle. Even when the evidence is right there in front of them, people don't care. At least not enough of them. They'd rather listen to their authority figure, or do what all their friends are doing. Which if you're doing what all your friends are doing it just turns into a circle jerk. But since they're in that circle jerk, they tend to just stay in it, and because the people in it are their friends or family, they defend it because it's their tribe. We're kind of hardwired that way.

TLDR, people are dumb monkeys.

Because religion evolved to thrive in us.

It's like a parasite, and our mind is the host. It competes with other mind-parasites like other religions, or even scientific ideas. They compete for explanatory niches, for feeling relevant and important, and maybe most of all for attention.

Religions evolved traits which support their survival. Because all the other variants which didn't have these beneficial traits went extinct.

Like religions who have the idea of being super-important, and that it's necessary to spread your belief to others, are 'somehow' more spread out than religions who don't convey that need.

This thread is a nice collection of traits and techniques which religions have collected to support their survival.

This perspective is based on what Dawkins called memetics. It's funny that this idea is reciprocally just another mind-parasite, which attempted to replicate in this comment.

I believe in religion. It definitely exists. Christianity, Buddhism, Hinduism etc. They all exist. Guaranteed.

How can you not believe in them?

Because they have enough evidence to satisfy them that they should, if they're rational; because they were taught to and never questioned it through self-examination, if they're not.

Note that evidence is not the same as proof; other users have pointed out examples of evidence such as 'testimony from trusted authorities such as parents' and 'personal spiritual experiences' and since those answers were very detailed I won't repeat them here.