Some do and some don't its true.
We've had a few bad years with Blight in England, damp summers that have been ideal for it to spread. For some stupid reason the EU has just outlawed the one decent thing we had to fight it with,
Bordeaux mixture, a copper based fungicide has been withdrawn from sale.
It not as though the stuff even gets into the plants, it sits on the surface and if you've sprayed tomatoes with it, you just wash it off before eating.
We've got a free service called Blightwatch,
http://www.blightwatch.co.uk/content/bw-Home.asp When conditions are right for a blight attack in your area, you get sent a text message to your phone and an email, so you know when to spray.