That's your assessment. The fact that Christianity as a whole is trending down (at least in Australia,) would suggest that people feel it is outdated and has little to no relevance in the modern world.
I was raised a Catholic, attended Church most Sundays, did my Confirmation and Communion. I chose Francis of Assisi as my saint protector, a rich man who gave up his the wealth that was his birthright to bring light to the plight of the poor and sick. I would then sit in a Church on Sundays owned by one of the wealthiest organisations on the planet that spent resources on covering up routine child sex abuse rather than resolving the problem and accepting that horrific things had been done by men of God under their stewardship.
You say that people don't "understand" Christianity. They understand what they are exposed to. There's something like 200 denominations of Christianity all with individual interpretations of the Bible and the teachings of Christ. Naturally adherents of any individual denomination think they have it right. The USA exists because Puritans didn't think the Anglican Church had it right. No different to Sunni Muslims thinking that the Shia branch has it wrong.
I don't think spirituality is the problem anymore, or even the belief in a personal God. We're not at the point yet (and may never get there,) where we can conclusively disprove God as a driving force, no matter how our expanding knowledge of the world and universe around us improves. Organised religion is a problem.
The old adage that a person is smart, people are dumb is applicable here.