And you are lacking in some basic history. Yes, most do have services in buildings, but they also have services in tents at different times of the years.
And all of these churches came from denominations which were famous for camp meetings, evangelical events and etc. Outdoor revival meetings were famous around the turn of the century. Additionally, when churches were shut down by local bureaucrats, the church4es would hold outdoor meetings near the jail or sheriff’s office.
A building does not make a church, Christ died for the people. We can worship as a group anywhere (sunrise Easter services on hilltops), the building just keeps us dry during the rain.
I am very aware of outdoor revival meetings, but they probably constitute about one one-thousandth of religious services - if that - even in the South. And those events are very dependent upon the weather, and would be impractical for much of the year in many climates. And I’m not sure why holding a service in a tent magically makes it more religious or more authentic.
It’s the services across the neighbor’s fence, in the mall, at the store and along the road that have a greater impact on saving souls.
Live your faith - not just wear it.