You just do, Freddy.

A lot of people don’t.

There’s a whole superstructure to religion - culture, ethics, public infrastructure, social networks, financial networks, a common history and language - that you need to supplement as you dispose of the older system.

What the European socialists discovered at the turn of the 20th century was that you can’t just burn down all the churches and start over from scratch. Anarchism without some new common social foundation just ends in civil war and foreign occupation.

Subsequent generations still need a scaffolding to cling to as they mature. And if that scaffold isn’t rooted in some new existential or moral foundation (or if it’s rooted in a rotten one) you end up with ultra-nationalism, or Victorian mysticism, or whatever paint Ayn Rand was huffing.