sasskins.....I have a certain amount of sympathy for your post.
Did IBS exist in the 50's, was it misunderstood and misdiagnosed? I don't know.
You mention lactose intolerance and food allergies......yes.......they did and do exist, but not, surely, to the extent that they are diagnosed today.
MRI scans still have not defined many of the "newer " psychological disorders and blood tests and genotyping have not delineated any "allergic disorders " and of course the patients today have the " advantage " of the Internet to confuse or mislead them.
No sass....I can't but empathise with your post.