Do you live near salt water? I am several thousand miles from salt water, have had virtually no problems with frames rusting out.
The first photo is an old Bridgestone mountain bike I bought from a neighbor. When his kids moved out, they left their bikes in the back yard. He decided to teach them a lesson by not putting the bikes away. Over a decade later, he was moving out and had to get ready to vacate the property. The Bridgestone had a 2 inch diameter (5 cm) tree growing up through the frame that he had to cut down so I could take the bike, it had been stored outside that long. I cleaned up the bike, changed bottom bracket, chain, rim tape, inner tubes, tires, some cables, a shifter, a saddle, pedals and grips. Hubs and other bearings were really thirsty for grease. I also applied Frame Saver to the frame, although the frame looked pretty good without it considering all those years outside. I still store it outside, second photo after I fixed it up, it is a great errand bike.
In the 1970s, I bought a used 1961 Ideor. (If you never heard of it, that is understandable, I had not either.) It had been treated rather badly, a lot of the chrome on the frame was virtually flaking off of it as there was a layer of rust between the tubing and the chrome plating. But the Columbus tubing, once I scraped off and lightly sanded had virtually no rust to be concerned about. Third photo is what it looks like now, I repainted it again this year. It has some 1980s parts on it and some modern parts, but the headset, seatpost, front derailleur, brakes (not levers, those are modern) and shift levers are original to the frame. It had a date code on the campy rear hub for 1961, the Brooks Pro date code was 1962. Fourth photo, I am sure it looks odd with modern brake levers to operate the early 1960s Mafac brakes, but I really do not like riding on the hoods of the vintage Mafac levers.
I am building up a new bike, received the frame yesterday and applied Frame Saver to the frame already.
http://velo-orange.blogspot.com/2014/02/frame-saving-and-rust.html