One of several coincidental factors

which led to the unfortunate success
of early Christianity was the laziness of the plebs*
who were first attracted by it. To be able
to stay put and pray and worship a conveniently
invisible god was a good deal easier than to traipse
from shrine to shrine, statue to statue, temple
to temple to offer money or petition for a better life
which was unlikely to arrive.  For much less effort
and ritual (apart from once-only baptism) they
could expect eternal happiness in an afterlife
in an overworld quite unlike the underworld that
Greeks, Romans and Germans expected.

* The demos of the Greeks, whose oafishness
will inevitably destroy demo-cracy.