It is always sad to see churches closed. But being realistic, it can cost (heating, insurance, maintainence) many thousands per year to even keep the smallest village church open. Our local church is a mile out of the village centre (the village moved from around it at the time of the black death !). So although it is used and well attended for marriages and funerals, it is sparsely attended on Sundays by the 'faithful' ... who are getting older. If we are practicing Christians, we should in theory tithe a percentage of our annual income to the church ... I think 5% is the suggested amount. But 5% of the pension of OAP's who still attend isn't enough to pay the tens of thousands a church has to find every year; hence all those coffee mornings, church fete's etc. The clergy aren't paid out of what is put in the plate on a Sunday ... they receive a stipend from the Diocese, and for that, have to minister in several churches in widely separated parishes. (I am talking country parishes here). Where do the dioceses get the money to pay the clergy ? Each parish has to pay a 'parish share' into the coffers .... so add that to the insurance, heating, repair costs !
So when you visit a well-known cathedral, don't be aghast when you see the notices about how much it costs to keep the place open to the public ... dig deep into your pockets, and pay up ! Small rural churches are quite a different kettle of fish. Many have to be kept locked (very sad) but if they are open when you visit to find your ancestors graves, then be generous and put money made of paper into the box on the wall ... a few pennies are just an insult to the unseen faithful who clean the church, do the flowers, cut the grass ...
When it comes to using churches for other purposes, yes, this is an excellent idea in towns ... I cite All Saints in Hereford as a good example of multi-useage .... they have converted a side chapel into an exhibition room for hire by outside persons; there is a vegetarian cafe (run as a business by others) at the back of the church; there are loo's ... and the main body of the church is still in use as a worship space. But this sort of thing can't be financed by the average small parish .... the cafe at All Saints was the turning point for that church, in that the church benefits from the rent.
So its a good idea for churches to be multi-purpose these days ... and even multi-faith ... but don't forget that like most things these days, it all comes down to MONEY !