First, the issue with lead paint was/is real. And it is more that just kids teething on a window sill. Either you don't have kids or simply forgot how much goes into their mouths totally beyond your control. And the reason that lead was removed from solder wasn't just because of the risk to electronics assembly workers. How many weekend hobbyists have exhaust hoods? I won't go on and add to the hijack of this thread but you are very wrong. Please PM me if you wish to discuss further.
Agree, I don't want to hijack the thread and delve into off topic subjects, but it isn't worth discussing in PM either, so I will keep this short. I will say the lead paint and asbestos scam has been the biggest farce perpetrated on the American people in the 20th century. We've created a cottage industry of abatement and litigation for both asbestos and lead.
As for lead free solder, this is on topic for this discussion if the consumer perceives it as a possible reason to sell/dispose of their consumer products (lenses) earlier than they normally would, which would, in theory, drive prices down. Again, lead free solder is a sham, period. So much so that the military won't use it or allow products they use to have it. Here's a good read on the subject of lead free solder if it interests you.
http://www.ecnmag.com/articles/2011/12/was-lead-free-solder-worth-effort
As for "How many weekend hobbyists have exhaust hoods?" why would they when most won't use more than a 4 ounce roll or rosin core solder in their lifetime. It's kind of a moot point and proves the foolishness of the lead solder ban.
I think there are other factors driving lens prices down. One reason could be digital photography is now so mainstream that it is a dieing fad since most people can now capture reasonable good images on their cell phones. You have to wonder how many of the younger generation want to drop thousands of dollars to buy gear the won't carry around unless they are being compensated for it. I think the days of advanced amateurs and hobbyists that wouldn't think twice about dropping $30K-$40K on gear are rapidly diminishing. I know I now think hard before I buy any new gear. And if I got to think more than 30-seconds about it I either don't want it bad enough or truly need it.