People pay to use a holiday let I own in Fife that used to be a chapel..

Like Dave's two examples, they might pay to use them, but not just to see them.
Historic ruins are in a different category.

Most old ruins that used to be churches are run by English Heritage, NT etc,

That is not true of churches that have just fallen out of use, which was what I said, and which stands.

"The churches were built to the glory of God, and still only exist as churches for the holding of services.

Some have indeed fallen out of religious use, and no-one would pay to visit those.

Churches may allow other events between services but, as I said, the services are the reason churches exist."