J.S.
I agree with what some of the other posts said and understand your reaction - it's a knee jerk reaction we all have to hearing something we don't want to hear - we look for 'a way out".
The increase in hearing about these surgeries does NOT necessarily mean they didn't have the hernias back then, it could mean that but it could mean that they didn't detect them (until later in life) or didn't correct them. Hard to know with some real research and a review of the relevant literature. From the little I know about hernias - they are something that causes acute pain when they occur rather than killing anyone so that's probably not the outcome to measure for.
Anyway, if you are uncomfortable you should inform yourself as much as possible about the condition (you can't trust the info you find on the web - seek advice from several professionals and maybe the NIH or Mayo clinic sites - trusted sites) and b) find a doctor you trust so you don't have to worry about their motives in advising you a course of action.
I agree too that the world is a dramatically different place then it was just 30 years ago let alone 70 with respect to pollutants yes but also the ability to keep babies born prematurely make it. Those few weeks really have an impact on babies ability to finish developing do lots of medical consequences are felt.
Whatever you decide, best to you and your little one. I also would be very upset at the thought of my little one undergoing surgery but if necessary would have it.