It's almost entirely caused by the "avoid peanuts during pregnancy" self-fulfilling prophecy (if you do so, chances are the next generation will be more allergic to peanuts).
That's interesting. During my wife's first pregnancy we ate peanuts all the time, and lived on peanut butter sandwiches. The kid nearly died when we first fed him straight-up peanut butter, and had to go to the ER by ambulance and give him steroids and epinephrine.
We've now been living in a peanut-free environment for the second child, yet the second child has no peanut allergy.
Obviously blanket statements like yours are ignorant. People develop allergies for various reasons, not just environment, or not just genetics.
Of course things were less well known back then, but there were also smaller communities, so there were less chances of running into people with allergies. Now we have social sites where we see the communication of thousands of people we've never met in real life. I only know 4 people will peanut allergies personally, and only live near 2 whom I see on a regular basis, yet in this thread, I've already read posts from 10 or more people with the allergy. My point is, just because we didn't hear about it as often back 50 years ago doesn't mean it wasn't a frequent occurrence. Other factors have to be accounted for.
Secondly, I've always wondered if a reason for less prevalence of allergies in the past was due to kids with allergies dying from the allergy without the allergy ever being diagnosed...
I remember using Pheonix when it first came out. It was quite nice at the time. It felt really lightweight compared to Mozilla.
From Wookiepedia: "When originally released in 1977, the first film was simply titled Star Wars, as Lucas was not certain if he would follow the film with a sequel. Following The Empire Strikes Back, the film was re-released in 1981 with the subtitle 'Episode IV: A New Hope'. The original version, without the subtitle, was not released until the 2006 limited edition DVDs. "
Link to Original Source